DO THE TON

Blood Sweat Tears and Grease => Projects => Cafe Racers => Topic started by: swan on Aug 05, 2012, 16:54:01

Title: Another Honda CB400F cafe racer
Post by: swan on Aug 05, 2012, 16:54:01
This is a bike build thread for a 1975 Honda CB400F Super Sport café racer with a series of catch-up images and an overview of the work I have done to date. This is my fourth CB400F crank up rebuild so I know this bike well but unfortunately I cannot keep this one for I need to sell it to finish my (overly documented) BSA Gold Star project. I am however building it as if I were keeping it and to my normal build standards. There are several bad cell phone images, so forgive some of the poor images.

It will be rebuilt with slight cosmetic and mechanical modifications and the goal is to have it look like a came from the factory with British stylings (black cylinder, Honda front drum brake, custom Manx single seat, Lucas tail light, clubman bars, Dunstall replica exhaust etc). I deliberately did not hack up the frame or make any modifications so it could be converted to stock should the new owner wish to do so. It will be very similar to two other CB400f’s I built and sold:
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1196.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/_MG_0127-Version2.jpg)



Honda CB400f’s were produced from 1975 to 1977 only as sleek, light and fast factory designed café racers. Café racer styled motorcycles did not sell very well in America in their day so in 1977 the handle bars were changed to be more upright and the foot controls more forward to appeal to American tastes. Only 5060 1977 CB400f’s were imported to North America. The CB400F has a cult following in Europe, Japan, Africa and America and most every part is available in NOS and/or aftermarket reproductions with a few notable exceptions.  Also, Honda parts are much less expensive than the British parts I have been buying lately.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/cb400grab.jpg)
The Honda CB400F is a marvel: It handles remarkably well, stops with authority, snaps through the gears precisely--and motors along smartly. The bike feels all of a piece, as if a hundred separate design systems fell into perfect synchronization. Yet the attraction of the 408 transcends its obvious competence. Even a card-carrying Anglophile would agree that the CB400F has real character. If you can't respond to the CB400F's electrifying mechanical presence, you should immediately switch your sport to checkers."--Cycle World, March 1975.


My bike is a low, low number (one of the first 750 ever built) and low mileage 1975 CB400f bought for cheap as a untitled basket case, missing the seat, tank, side covers, brake pedal but basically a roller (sorry, no dramatic “before” image). I titled and registered the bike and then stripped, cleaned, prepped, primed and painted the frame and put it in storage while I worked on my BSA Gold Star.  During that time picked up a tank, side covers, brake pedal and a few other missing bits along with new bearings, seals and gaskets, hardware, tires and more. My friends and I now have a proper workspace (the Winona Riders workshop) and a lift table so I am now finally building this bike. I hate to sell it, but I have a Gold Star to finish and ride so here we go:


Frame and Forks:

The frame, triple trees, stands and other black bits were cleaned, inspected, prepped and painted with a two-part catalyzed gloss black automotive paint. The swing arm was installed with original bushings (still good). I cleaned up the rear shocks and installed them.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/_MG_2933-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0962-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0971-Version2.jpg)

The original fork tubes are in fantastic shape with no wear or rust anywhere. They are the best I have ever seen on an old Honda.  I meticulously cleaned everything and sanded, polished and buffed the sliders. New OEM bottom bolts, copper washers, dust caps and forks seals were installed. They were filled with fresh fork oil and work perfectly.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/_MG_3091-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/DSCN2940.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0975-Version2.jpg)

Wheels
Although not for everyone, I used a Honda CL/CB 360 front drum brake on this bike. Many people are quick to hate drum brakes yet have not made the time to learn how to set them up, adjust and maintain them correctly. To my eyes they not only look better on a café racer than disc brakes, they do in fact work very well. I simply hate dealing with brake fluid (its feel, smell as well as its paint removing abilities) though I have rebuilt more Honda master cylinders than I can remember. I am also rebuilding the original front wheel and disc brake system with a great rim and new spokes as an option for the future buyer.
 (http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0894.jpg)
The front drum was in good shape so I dissembled everything for cleaning and polishing. The rim was in poor condition so I bought a correct used 18”rim in very good condition, (Honda no longer sells 18” DID rims in the US, grrrrr) The old factory finished of the plate and hub was removed with aircraft paint stripper, wet sanded with 400 to 1500 grit sand papers and polished and buffed with black, brown, red and white compounds. I laced and trued the rims with new spokes and nipples, pressed in new bearings and added new tube, rim strip and a new 100/90/18 Dunlop D404’ tire. I had a local shop dynamically balance both wheels on their computer. I got the front wheel perfect but the rear needed a few weights.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0912.jpg)
stripping factory finish
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1239-Version2.jpg)
Beautiful and functional.

The rear hub was an absolute nightmare and took a lot of time and energy and I considered buying another used one, but in the end I tackled it. Good thing I like a challenge. It was covered in rock hard grease, oxidation and the brake shoes were frozen to the drum and the sprocket was not coming off until the BFH (big fuckin’ hammer) appeared.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0852.jpg)
The OEM chain cover over the sprocket was removed by drilling out the rivets and though I repainted it, decided not to use it.  After degreasing, scrubbing and media blasting, I painted the hub and cover with VHT silver paint and heat cured the parts in my oven. New bearings were pressed in, the rim polished, new spokes and nipples laced and trued the rims to .005” lateral and radial tolerence. The hardware was zinc plated, new brake shoes and springs and a new sprocket was installed. Both hubs were spun on the stand and I used varying degrees of sandpaper to remove the crud, rust and bring inner drum lining closer to truth.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0947-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0949-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0957-Version2.jpg)
Media blasted

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0979.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0980-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_0974-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0858.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1249-Version2.jpg)
Ahhhh, much better

To determine the correct offset of the rear hub I centered the front rim between the forks, laced and trued it. Next I ran parallel straight edges from the trued front rim to the loosely laced rear rim to determine the correct position relative and in line to the front. then I measured the offset on both sides and then trued the rim in my stand. The centers of both rims are perfectly aligned.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0866-Version2.jpg)
Centered front rim
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0869.jpg) front to..
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0870.jpg) …rear
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0868.jpg)
...to determine alignment and rear rim offset
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0872.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0873.jpg)
with the correct offset the rear rim was trued on the stand
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0874.jpg)

I mounted new Dunlop D404's (100/90/18 front and 110/90/18 rear), tubes and rim strips and got to one of the best moments of any build; ROLLING CHASSIS!
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0887-Version2.jpg)

Motor rebuild coming next…
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 05, 2012, 17:33:13
Motor Rebuild

Here is a quick overview of the motor rebuild. Nothing fancy or tricky, but I took my time to do it right following the factory service manual and a Haynes manual. Cleanliness was important as well as measuring everything, taking notes and using plenty of engine assembly lube. Any part that questionable or bad was replaced. The engine cases were cleaned, degreased, prepared, painted and heat-treated with Dupli-Color VHT aluminum 1615 paint. Three sessions of oven curing 150, 200 and 300 degrees F hardens the paint and make it oil and gas resistant.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/DSCN2079.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/DSCN2074.jpg)

Next was a meticulous crank up rebuild, ensuring all components are to factory specifications. Anything that was out of spec or questionable was replaced with Honda OEM parts. All new seals and gaskets were used. The rotor is difficult to remove without the proper Honda service tools (which I purchased but was given the wrong size). I opted to borrow a heavy puller from an O’Reilly’s auto store to remove it (along with PB blast and heat it came off easily) New seals were installed on each end of the crankshaft.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0817-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1043.jpg)

All the crankshaft journals were measured, the bearings checked with Plasticgauge and fortunately everything was well within factory specification confirming this is a low mileage Midwest bike that saw little abuse or use. The cam chain guides show little to no wear and everything inside the motor looked great, no drama, all good. (http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0823.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1038.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1042.jpg)

The cylinder, pistons and rings were cleaned and checked, all good.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1073.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1070.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1069-Version2.jpg)

New main shaft bearings and snap rings were installed, the transmission, cam chain guides were inspected and then I buttoned up the lower end sealing each half with Yamabond. All good.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1056.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1060.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1061.jpg)

The cylinder was soda blasted and painted (non-stock) gloss black with VHT paint and heat cured in three cycles.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG0835-1.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1080-Version2.jpg)

The cylinder head looked awful and took several hours to degrease, dissemble, clean, soda blast, prepare and painted high temp black and heat cured. One valve head was corroded so I replaced it with another I had in storage. All the valve stems, springs and goods were to factory specification so the were cleaned and the valves ground in and installed.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1078-Version2.jpg)
yuck
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1077-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1166.jpg)

The motor was placed in the frame by myself (easy and lighter than a CB750 motor) I have done many time before and use pipe insulators to protect the frame.)

The oil pump was dissembled, inspected and cleaned. All good. put in the starter, new sprocket and chain and installed the left hand cover. All the threaded holes on the engine cases were chased with a greased tap and I used a stainless steel allen bolt kit for all the covers with anti-sieze lubricant on the threads.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1089-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1232-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1231-Version2.jpg)

The gear change assembly was cleaned and installed. Clutch was in good shape and plates and springs have plenty of life left in them so they were cleaned and installed. I made a service tool to torque the clutch hub nut. An old socket cut to fit the four slots on the nut, not pretty but effective. I polished the clutch inspection cover and roughed in the clutch cable so it functions, but I will shorten the cable later this week.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1205.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1085-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1230-Version2.jpg)

New chain and sprockets were also installed as set. I did drop the front sprocket to a 16 tooth based on research and others’ recommendations. The 6-speed transmaission has a short first gear so this may help a bit.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1193.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1147-Version2.jpg)

Exhaust
The OEM 4 into 1 exhaust was in good shape, not perfect, but good.  This piece of plumbing with its sexy, swoopy and curvy bends is one of the most beautiful headers ever. New Old Stock (NOS) ones are selling for $1200 and up on Ebay. I see David Silver Spares in the UK are selling very nice reproductions but I am sticking with this one and after cleaning and polishing it it looks pretty good.  Also I soda blasted the exhaust collars and they look great. I bought a replica Dunstall muffler and with some extra baffling. The Emgo Dunstalls work and sound better when you replace the tissue paper thick fiberglass that comes with them with better baffling. I run two Dunstalls on my Triton with the same set up.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1150-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1216-Version2.jpg)
original baffling
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1218-Version2.jpg)
Moose baffling

I was inspired by this video:
http://youtu.be/MBVup4Mve5M

Next
I spent a lot of time, money and energy tracking down and buying a lot of the little bits that were missing as well re-zincing most of the hardware. The motor, exhaust, rearsets, brake pedal, kickstarter etc were finished and installed last night and I set the valve tappet clearances so I can now add oil, do compression and leak down tests and then start work on the carbs, electrical, tins and seat. Stay tuned…
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1224-Version2.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: NeightRG on Aug 05, 2012, 17:54:19
I'll be watching this build very closely... Closer than most. Looking good.
Title: Re: Another Honda CB400F cafe racer
Post by: andycafe on Aug 05, 2012, 20:15:11
gee you have been a busy boy  ;) lucky new owner to have you rebuil this, good job.....
Title: Re: Another Honda CB400F cafe racer
Post by: BigRedButton on Aug 05, 2012, 20:17:00
Again, epic.
Title: Re: Another Honda CB400F cafe racer
Post by: Big Rich on Aug 05, 2012, 21:04:52
Yup......signed up for sure.

Great work Swan - the future owner should be very happy with a "new" 400F.
Title: Re: Another Honda CB400F cafe racer
Post by: Worst cb650 ever on Aug 05, 2012, 22:51:39
I'm onboard - it looks awesome!
Title: Re: Another Honda CB400F cafe racer
Post by: VonYinzer on Aug 06, 2012, 00:48:14
Neat-o.
Title: Re: Another Honda CB400F cafe racer
Post by: Kwality on Aug 06, 2012, 03:01:43
Your work and documentation are top-notch.  Count me in!
Title: Re: Another Honda CB400F cafe racer
Post by: wilber551 on Aug 06, 2012, 03:31:49
Your work is very respectable. I'm also building a 1977 400F. Ill be watching
Title: Re: Another Honda CB400F cafe racer
Post by: JustinLonghorn on Aug 06, 2012, 11:10:04
I can definitely dig it, sir. I am on board.
Title: Re: Another Honda CB400F cafe racer
Post by: Owned on Aug 06, 2012, 12:38:44
Looks like a nice stocker rising from the grave!  Love these 400's.  Great platform to work with. 
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 06, 2012, 14:14:12
Thanks all! I was not going to do a build thread for this bike at first, but I changed my mind and will keep the updates and images coming.

Last night I added oil and kicked it over to get the oil into the internals but did not test compression yet. No leaks, drips or errors.

Started on the electrical, bought and charged a new battery and dug my way through three wiring harnesses that I picked up over the last few years.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1254-Version2.jpg)
Two are hacked, spliced, duct tape, wrong connectors and wrong color extension wires-total amateur hour and a pile of useless spaghetti.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1260-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1261-Version2.jpg)
The third was dirty but unmolested with the correct part number so I cleaned it up. The fuse holder is broken but usable.

I have three left hand controls but did not think any of them are for this bike. I hit the service manual, wiring diagrams and multi-meter to sort it out and ended up repairing a bad HI/LOW switch on one control and it is the correct one.  I need to take it apart, drill a hole for the wires on the side to fit the clubman bars and paint it to match my new OEM right hand control. The old right side controls ALWAYS have a broken or fragile starting button, so it is best to start with a new one. Of course the left hand control is no longer available from Honda in the US, but they are still available in the UK and EU.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1265-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1267-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1271-Version2.jpg)

I have a busy couple of days at work and socially but will work more on this bike later this week. I want to get this thing running within two weeks. Stay tuned...
Title: Re: Another Honda CB400F cafe racer
Post by: john83 on Aug 06, 2012, 21:17:43
Good stuff. Very nice work.
Title: Re: Another Honda CB400F cafe racer
Post by: bwald on Aug 11, 2012, 19:40:02
I was watching Swan working on his seat all afternoon today. This is going to be a sexy bike when it's done.
Title: Re: Another Honda CB400F cafe racer
Post by: ronnie on Aug 12, 2012, 02:52:30
Checking in for this thread..
Title: Re: Another Honda CB400F cafe racer
Post by: OneArmWillie on Aug 12, 2012, 04:36:56
This dude knows how to make a build thread.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 12, 2012, 13:50:33
Thanks all, a quick update: The electrical is 98% sorted, tested and installed and my left hand control is painted, assembled, tested and installed. It looks good and works great. I found a good fuse holder in a box of spare parts.

I am greatly inspired by Oldog's thread on making a fiberglass seat mold and producing a seat pan http://www.dotheton.com/forum/index.php?topic=3070.0 and decided to buy the materials to do this. One, so I could learn the process and two, I want to produce seats for my CB750, KZ400 and possible other projects for guys in our shop. This will be a Manx style seat with black marine vinyl covering the entire pan with red piping to match the tank.  I took detailed measurements of my tank, frame and rear fender and made a cardboard template.  It is important to me that it uses the stock locking mechanism and hinges and I want it to look like it could have come from the factory.

Next, I glued with a hot glue gun pieces of scrap foam insulation I had been saving and marked out the general shape and form. The rough form was cut with a hacksaw blade and hand saws. Next,I used rasps and rough sandpaper to get to the final form. More sanding with finer grit sandpaper and then coated the plug with lightweight body filler.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1324-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1326-Version2.jpg)

With more rasp and sandpaper work, additional coats of filler, I am nearing the final form of the plug and plan to finish filling and sanding it tonight so I can paint it with a two part epoxy primer and then create a mold from it
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1385-Version3.jpg)

From this plug I will make a mold from which the seat will be cast using black gel coat, epoxy resin and airplane grade carbon fiber I friend gave to me. It will take several days for the mold and cast pan to be made and cure so I plan to start on the carbs during the drying process.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1308-Version2.jpg)
They are complete, and are not in terrible condition but I plan to spend many hours inspecting, cleaning and rebuilding them with new carb kits. Each step is one closer to a finished bike.
Title: Re: Another Honda CB400F cafe racer
Post by: juan@crqcycles on Aug 17, 2012, 00:39:17
COMPLETELY BEAUTIFUL BIKE! You sir are an artist! I can't wait for the finished bike!!! The detail you put into every little nut and bolt...congratulations!
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 19, 2012, 19:37:45
Thanks!

Updates: Carbs are done and the seat mold complete

I made time to finish cleaning and rebuilding the carbs. Overall, I spent 6 hours dissembling, cleaning, rebuilding and setting them up and I really need to be in relaxed frame of mind to do this detailed work. I soda blasted the bodies and the interior of the bowls. The exterior of the bowls and caps were polished on the buffer.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1467-Version2.jpg)

We have all been here before, years of sitting, dirty exterior and varnished gasoline in the bowls-yuck:
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1477-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1478.jpg)


New rebuild kits, #80 main jets and lowered the needle clip one notch (raising the needle). I used the same set up on other CB400f's and this will be my baseline for tuning with K&N pod filters, stock header and Dunstall replical muffler. Plug chops and a carb synchronizer will be used to determine the final carb set up.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1486-Version2.jpg)

This was one of the best set of carbs I have worked on. Dirty, yes, but no corrosion of metal, zinc plating is in great shape, nothing missing. Someone had been in the lower portion before, but not the top parts. The slides are prisitne:
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1487-Version2.jpg)

The floats had undersized pins and drill bits holding them loosely in place and they were set to the wrong height. I threw them out, bought the correct diameter rod stock from a model/hobby store, cut to fit and installed. They work correctly and I set the float heights to 21mm.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1494-Version2.jpg)

The only drama was on the carb number 4 float bowl screw. It was very tight even after soaking in PB blaster. I was literally walking over to grab a propane torch to heat it and I made the mistake of trying to turn it once more and it snapped off. F#$%!
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1490-Version2.jpg)

The broken piece came out easily with a screw extractor and I replaced it with a spare screw from one of my shop mates, thanks Andrew.
The carbs done and installed on the bike. I will shorten the stock throttle cables and install them this week.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1509-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1510-Version2.jpg)

SEAT

Since I am making a mold from which to cast a seat, there is much more work and several more steps involved then simply casting a seat off a plug. Again, Oldog's thread was of great help and I am bodging my way through this to learn the process and made a few mistakes which I corrected and learned from so my next attempt will be better. I am experienced with fiberglass and resins but not gel coats.

The sanded plug was sprayed with multiple coats of two part automotive sealer/primer and wet sanded with 220 to 1000 grit sandpapers. Next three coats of Partall Wax was buffed on and then topped with a PVA mold release film. The beer is optional.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1431-Version2.jpg)

Next, several layers of black tool gel were applied with a brush. I do not have a dedicated spray gun for gel coats (yet). Things went bad on the second coat and there was some wrinkling which could be attributed to an inaccurate mixture of the gel and catalyst or most likely too thin of a coat due to brushing, not spraying. From the Fibre Glast website:
"A coating less than five mils thick may wrinkle, especially when brush marks are present. Check the thickness using a gel coat thickness gauge. The preferred thickness is .010" to .020". Live and learn....
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1437-Version2.jpg)


After the tooling gel set, layers of fine weave fiberglass and epoxy were applied followed by two layers of a heavier fiberglass mat. The mat may have been too thick, was difficult to work with, leaving me with some air bubbles on the final coat (whitish areas). The mold ended up being very solid and will work well, but just looks ugly. For the next mold I will start with fine veil, regular weave and then a single layer of lighter weight mat fiberglass.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1498-Version2.jpg)

The plug was removed and the inside of the mold was washed with soap and water to remove the release film, The wrinkling in the tooling gel left valleys which will show up on the seat if cast as in, so to correct this I filled the valleys with a few rounds of light weight body filler, sanding and then sprayed the same catalyzed primer sealer I used on the exterior of the plug. Then the mold was wet sanded up to 1000 grit, waxed and sprayed with release film. There are still a few minor imperfections in the surface of the mold. I can live with them since the final seat pan will be upholstered.  The flaws are more obvious on the flange of the mold, but that part will be trimmed off.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1503.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1504.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1507.jpg)

Tonight I will brush several layers of tooling gel into the mold and plan to lay some fiberglass and carbon fiber tomorrow, have a seat pan by Tuesday and start sewing a cover on Wednesday. Stay tuned...
Title: Re: Another Honda CB400F cafe racer
Post by: andycafe on Aug 20, 2012, 07:22:46
Awesome work, wanna rebuild my set of carbs too?lol.....
definitely staying tuned for your seat.... :D
Title: Re: Another Honda CB400F cafe racer
Post by: joeficsit on Aug 21, 2012, 15:12:50
I have got to get off my butt and start to work on my projects. Looks great sir. Can't wait to see the finished product.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 22, 2012, 10:48:27
Awesome work, wanna rebuild my set of carbs too?lol.....
definitely staying tuned for your seat.... :D
I will if you buy the beer....

Alright, seat update: I brushed three layers of black gel coat into the waxed and PVA release film coated mold-
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1514-Version2.jpg)

After it dried, I added a layer of fiberglass and epoxy resin. I use West Systems 105 epoxy and 205 hardener because I am experienced with it.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1516-Version2.jpg)

And then a layer of some thick woven carbon fiber-
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1519-Version2.jpg)

After it dried I popped he seat out of the mold and trimmed the flanges. Looks good with a few minor defects that I will touch up. It is very lightweight and strong.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1521-Version2.jpg)

I plan to do the touch ups, the final cutting and sanding of the edges tonight along with adding rubber spacers and a hinge and then on to foam and sewing a vinyl cover. Also my new K&N filters arrived so they will go on too. Stay tuned....
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1522-Version2.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 26, 2012, 12:29:15
Another update, she LIVES!!! Fired her up, timed the ignition and she is running well. Sounds great with the Dunstall muffler. Carb #2 is a bit intermittent and I have determined it is not the coil or the plug so I need to examine and clean carb #2 again and plan to do so tonight.

Cables:

I shortened the throttle and brake cables to fit the clubman bars. I use a ferrule or wire stop as the new end. After carefully measuring the existing exposed part of the cable, I measure and cut the sheathing to the length I want. I cut the cable and sheathing with a cutting wheel on a Dremel, clean with carb cleaner, slide ferrule to postion, tighten the screw, flux, solder and then cut and sand it to shape. This method works great.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1533-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1537-Version2.jpg)
Voila!

Tank:

I had done much of the prep work on the tank prior to storing it. There were a few small dings which I filled with body filler, sanded and primered. I did some tiny spot filing, seal and sanding guide coats, sanded again and then a final coat of grey primer.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1543-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1544-Version2.jpg)

I found Plastic-Cote Honda Milano Red is very, very close to the original OEM CB400F Honda red.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1539-Version2.jpg)
Original OEM Honda red.

I sprayed several light, even coats of the Milano Red followed by three medium coats of catalyzed auto clear coat. I will let this sit and off-gas for a couple of days, wet sand, add the decal and spray more coats of clear. Then more fine sanding and buffing with several grades of compounds and glazes until done.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1551-Version2.jpg)

I will clean the inside of tank one more time before adding fuel. If you are going to do it, do it right- new OEM petcock and fuel cap for the freshly painted tank.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1547-Version2.jpg)

Still need to paint the side covers, and headlight bucket, finish mounting and upholstering the seat, paint the undersides of the fenders and few other minor things and soon she will be ready to take out and shake down. Stay tuned...
Title: Re: Another Honda CB400F cafe racer
Post by: juan@crqcycles on Sep 10, 2012, 23:05:30


Show us more pics please!
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Sep 12, 2012, 10:50:05
Show us more pics please!
Here ya' go... Quick update:

Tank and side covers are clear coated with graphics. They will be sanded, polished and waxed, but look good already.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1624-Version2.jpg)

The seat was a challenge to line up correct with the stock locking mechanism. I made hinges and cut and pop riveted strips of aluminum as 'teeth" to hold the vinyl seat cover in place once it is stretch over the sides of the seat. Tonight I should be able to sew a seat cover and mount the seat. Stay tuned.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1626-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1630-Version2.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: john83 on Sep 12, 2012, 18:40:02
That paint really came out looking great!
Title: Re: Another Honda CB400F cafe racer
Post by: juan@crqcycles on Oct 07, 2012, 00:46:01
Hey! What happened with this bike? DOne already?
Title: Re: Another Honda CB400F cafe racer
Post by: Kwality on Oct 07, 2012, 10:51:02
+1  any updates Swan?
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Oct 07, 2012, 14:50:25
Sorry all, I have been busy with work and other projects. I did however finish polishing the tank last night. Looks good, and plan to install the cap, fuel line and petcock tonight.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1834-Version3.jpg)
I use a heavy duty DeWalt variable speed buffer, several different 3M brand cutting, polishing and final glaze compounds on small wool and foam pads to polish clear coat.
(http://i170.photobucket.com/albums/u272/66triton/1962%20BSA%20DBD34%20Gold%20Star%20project/_MG_6043-Version2.jpg)

I have been struggling with getting power to the headlight and taillight. I t is not a grounding issue and after many frustrating hours with a multi-meter now believe I may have the wrong left hand control switch. Gonna work on it some more tonight. Once that is sorted It is time time to install the front fender and start riding and shaking her down.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Oct 18, 2012, 12:01:51
She is alive! Took her out last night for the first of many shakedown rides. So far so good, a couple loose bolts but no other problems. Wow, the repacked Dunstall replica sounds amazing! Runs, shifts, stops well and revs without hesitation all through the throttle range. Need to weld a crack on the front fender mount and install the fender and start doing plug chops and carb synching. I will try to post a video with her lovely exhaust sound soon. Fun!
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMAG1090.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: JustinLonghorn on Oct 18, 2012, 12:04:10
Very clean, sir!
Title: Re: Another Honda CB400F cafe racer
Post by: juan@crqcycles on Oct 18, 2012, 14:01:36
Beautiful!
Please upload the video!
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Oct 19, 2012, 19:05:00
Thanks all! Still shaking her down. Sounds great but needs some carb work and synching. Hopefully I can make the time tomorrow.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1938.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: john83 on Oct 19, 2012, 21:57:33
That's a fine looking scoot there, sir.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Oct 21, 2012, 22:01:57
Thanks all! Spent all yesterday fettling, carb tuning and tweeking, test riding and dialing her in. Still needs a tiny bit of carb work but she accelerates, handles and turns like a dream. The repacked Dunstall replica sounds amazing! Electric and kick starts with ease, clutch is perfect, tranny is smooth and easy to shift, suspension is responsive and comfortable and she is a blast to ride. Here are few quick pics after my ride tonight and I have humbly accepted a nomination for Bike of the Month for this beast.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1983.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1979.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1980.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1995.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2000.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2001.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1981.jpg)
Title: Re: Another Honda CB400F cafe racer
Post by: andycafe on Oct 22, 2012, 08:19:07
Sweeeeet ;D
Title: Re: Another Honda CB400F cafe racer
Post by: Wangofree on Nov 02, 2012, 16:45:10
. . .  and I have humbly accepted a nomination for Bike of the Month for this beast.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1979.jpg)

Rightly so.  Fantastic work.  Extremely impressive.
Title: Re: Another Honda CB400F cafe racer
Post by: 3DogNate on Nov 02, 2012, 17:57:44
I like it... those headers look so cool. Clean build... be proud.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Nov 06, 2012, 13:26:33
I am having a challenging time getting my bike to idle correctly with individual K&N pod filters. There are dozens and dozens of threads online (Do the Ton, SOHC, Yahoo Auto Groups, et al) discussing this very problem and most say it cannot be done. It can be done and I have successfully run pods on three other CB400f's using stock exhaust, dropping the needle clip one notch and running 80 or 85 main jets. This bike has a repacked Dunstall replica muffler (which sounds awesome!), stock 4 into 1 header, 80 main jets, raised the needle one notch (lowered the clip, enriching the mixture to compensate for more incoming air) and a #38 pilot jet. I have quadruple checked timing, ignition, valve clearances and confirmed there are no vacuum leaks. The carbs, floats levels all passageways etc have been meticulously cleaned several times and set to spec. I am at 700 feet elevation and it is generally in the 50's farenheit when I am doing test runs and plug chops. The bike runs extremely well above the idle circuit, but down low it idles high, hangs, then drops down to a too slow of an idle. This has nothing to do with mechanics of the carbs (slides, springs, throttle cables etc) I believe one or more of the pilot jets are fouling, causing the idle to drop. This has made synchronizing the carbs at idle difficult.

Well, last night I did a series of compression tests with the engine cold, wide open throttle (WOT), cold with a bit of oil squirted into the cylinders and WOT and after I ran the bike around for awhile. Cylinders 1,2,3 were consistently in the 130's psi on all tests with my cheapie compression gauge. Cylinder #4 was 75 psi cold, 85 with oil added and 80 psi after running, telling me there was a leak in the valves, not the rings or cylinder on #4. I checked the torque on the cylinder head and all bolts were tight and to spec. There are no air leaks around the cylinder head or gasket area. So, off with her head-I ripped her down to lower end last night. I knew the chamber of cylinder #4 had some pitting and corrosion which came with the bike. I did lightly lap the valves with rough and fine compounds when I rebuilt the motor.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2062-Version2.jpg)
#4 on the right, note the pitting.

What I discovered was some of the pitting and corrosion was also in the inlet valve seat of #4, allowing for a slight leak, causing the low compression reading. In a dark room, I shined a strong flashlight into the inlet and exhaust ports and discovered two tiny light leaks on the inlet valve seat, the culprit of my compression leak. If I did it right the first time, I would not be doing this now.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2064-Version2.jpg)

I am meeting with a machinist friend today who has the proper sized valve seat cutters. Hopefully, we can lightly cut the valve seat in order to remove the two small areas of pitting without having to replace the whole valve seat (time and $$$$).

As long as I am at it, I am replacing the kick start quadrant with a slightly used one with better splines than my original.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2057-Version2.jpg)

With 4 cylinders of even compression I should have an easier time dialing in and synching the carbs and fixing the idle problem. I'll post my results, stay tuned....
Title: Re: Another Honda CB400F cafe racer
Post by: JustinLonghorn on Nov 06, 2012, 13:37:21
Sorry about the damage, but at least now you know the main culprit and you can move on from here.

Keep at it, sir. She sure is a purddy scoot.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Nov 06, 2012, 16:16:49
Thanks again Justin. Wow, I got lucky! I stopped by my neighbor's shop, he has all the proper tools and he touched up my valve seat over my lunch hour. I even had time to vote. He is an experienced motorcycle machinist  and the good news is I do not need a new valve seat. With the touch up, the valve stem height only increased .004". He also offered to skim my cylinder head tomorrow too! All for the price of twelve hoppy and dank bottles of IPA. My kind of trade. He is setting up his shop, mills, lathes etc to only to do work on motorcycles. I will post his information in the coming months once he is ready to go back in to business.

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2064-Version2.jpg)
Before
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2066-Version2.jpg)
After

After the head is skimmed I will reassemble the motor and hopefully this will resolve my idle issues. Onwards and upwards...
Title: Re: Another Honda CB400F cafe racer
Post by: john83 on Nov 06, 2012, 19:41:57
Nice! That's my kinda deal right there!
Title: Re: Another Honda CB400F cafe racer
Post by: HonDave on Nov 07, 2012, 14:27:29
Hey guys, not to just barge in on the thread but I've been drooling over it for a few days now. An old guy near me has a 76 400f for $500. Missing the seat, bars and header (damn). Anyways it seems like a great bike all around especially for my girlfriend to ride and it's a Honda so it should be a fun time rebuilding, I guess I'm just wondering if there's any dark secrets about these bikes or anything i should know before i get knee deep in Honda parts.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Nov 07, 2012, 15:07:28
Dave, no worries, these are great bikes, one of Honda's finest. They run like Swiss clocks (once tuned and synched), scream all the way up to 11,000 rpm's and are fast, light and extremely easy to handle. If you (or your GF) are taller or bigger I would consider a Honda 550. Most parts are available from Honda and some of the missing bits are available from David Silver Spares including new 4 into 1 headers.  Used seats come up on e-bay often and new seat covers are around $70. Bars are available as is the right hand control. The left hand control is not offered by Honda anymore but you can find new ones from DSS or Japan or buy a used one. No real dark secrets, but make sure the cam chain and tensioners are within factory spec and the carbs are clean and in synch. Also, a stock airbox will make your life easier.

If I did not have a Gold Star to finish I would keep this bike in a instant. It will be difficult to sell this, but since I have found three before this one, another will come along in the future.

PM me your e-mail addy and I will send the original brochures, reviews and other information and links to the parts and service manuals.
Title: Re: Another Honda CB400F cafe racer
Post by: Worst cb650 ever on Nov 07, 2012, 20:25:08
Swan, are these the Hondas with the more set back foot controls?  I seem to remember reading something (perhaps from you) about one Honda bike with almost rear sets for the first few years of the model run. 
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Nov 08, 2012, 13:50:22
Worst CB650 Ever, yup, there were Honda's first production Cafe Racer and the 1975 and 76 models had rearsets. IN 1977 they were changed to be more forward. My bike is one the first 750 CB400f's built and has the early style rearsets.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_1232-Version21.jpg)

I nearly finished rebuilding the motor last night. I still need to install the exhaust and carbs and run it tonight. With the valve seat repair and the cylinder head skimmed, compression in #4 is much, much better! I will post results after I ride the bike tonight.
Title: Re: Another Honda CB400F cafe racer
Post by: JustinLonghorn on Nov 08, 2012, 13:55:09
So clean, man!
Title: Re: Another Honda CB400F cafe racer
Post by: Maritime on Nov 08, 2012, 14:18:20
Wow good to hear Swan, I wish I had the $$ to just buy this bike from you. I would fly to your place and just ride it home.  I want one since I rode Justins and yours would be like buying a new one.  Hope you get top dollar when you do sell her to put towards the goldie.

Cheers,

maritime
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Nov 25, 2012, 17:55:47
Maritime, thanks, this bike is going to be hard to sell. She runs and rides so well. The good news is I picked up another 1975 CB400f last weekend! It was cheap, titled, but a 500 mile round trip drive with a trailer wheel blowout, but worth it. I spent a few hours cleaning 30 years of dirt and barn dust off the new one, cleaned the carbs, new battery and put the tank from my last CB400f and she started up and ran well. A bit more fettling and a Dunstall replica muffler she went out for a ride. Runs great! I have not decided what I going to with the new one yet, Cafe or restore, keep or sell, hmmmm.... I will start a separate thread for this CB400F (my fifth one!):
(http://i170.photobucket.com/albums/u272/66triton/1975%20Honda%20CB400F%20number%205/IMG_2117-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/1975%20Honda%20CB400F%20number%205/IMAG1135-Version2.jpg)
Trailer wheel blowout but thankfully it was empty and on my way to pick up the new girl.

My current CB400F took a hell of a lot of carb work, tuning, tweeking, troubleshooting and synching to get it right. The machine and valve seat work raised the compression in cylinder #4 to the level of the other three cylinders but did not eliminate my idle problem completely. I have never had a problem with pods on a CB400F before, but this one gave me grief at idle, so I went back to the stock air system for a baseline comparison but it still had the same idle hang and richness at idle, therefore it was not the pods causing the problem. I am not the only one with this issue (Google "CB400F idle hang"...) I pulled and completely cleaned the carbs, idle circuit, mains, airways, emulsion tubes, raised and lowered the with the float levels 1 mm, played with #38 and 40 pilot jets, checked and reset valve clearances, retimed and verified timing advance bob weights were lubricated and working correctly, etc, synchronized with 4 gauge carb synchronizer, used Yamabond between the carb insulator boots and cylinder head to eliminate vacuum leaks, installed a new Honda Air filter, new air intake rubber boots, etc but still had an issue at idle. #@#%&!
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2104-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2068-Version2.jpg)

I was getting frustrated but by the process of elimination I now believe the issue is with the aftermarket carb rebuild kit components themselves. The common belief is that the aftermarket needle and the stock Honda emulsion tube do not seat well together at idle, allowing too much fuel to pass, enriching the idle circuit causing it to rev up temporarily, then fouling the plugs, causing a drop down to a poor idle. Also, I measured the stock Honda air screw's diameter versus the aftermarket screw's diameter and found the Honda one is slightly (.005") larger. This may be also causing idle problems(???). So, I installed the OEM air screws.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2107-Version2.jpg)
Aftermarket top, Honda OEM stock air screw bottom.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2268.jpg)
Cleaned the holes of the emulsion tubes.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2269.jpg)

I cleaned the carbs from the new CB400f (#5 as I call her) and left the stock OEM Honda components in and installed them on to this CB400F (#4) and voilá, she runs great at idle and all through up to wide open throttle. I am unsure if my aftermarket carb parts are K&L or Keyster brand for they are in unmarked white boxes. I will dig through my receipts to see what brand they are and post so others can avoid them.  A long hard lesson learned: use OEM Honda replacement parts in your carbs.

So, with a properly carburetted bike I have completed 80 shakedown miles and she runs and rides extremely well. I changed and examined the oil and filter at 50 miles and nothing was wrong. Thanksgiving in Minnesota was 63 degrees fahrenheit! Normally I go snowboarding, but I took the bike out for what may be the last time this year and rode nice an easy and then hit the empty back roads and opened her up. She does well at 80 mph plus, so smooth, great handling and by far the absolutely best sounding Honda I have ever heard. Back at the shop, I retorqued all the bolts, head, axle caps, etc and need to clean her up and try to sell her. It is a bad time of year to sell bike around here but I may try E-bay her or wait until spring to realize my reserve price of $3500. I did however order matching Honda carb emulsion tubes and needles from Honda (needle jet set OEM#16012-377-004) and will install them and test and synch the carbs one last time.

Here are some useful links to RichB's and other CB400f carb woes at idle:

http://forums.sohc4.net/index.php?topic=100845.msg1126616#msg1126616
http://forums.sohc4.net/index.php?topic=51957.450
http://forums.sohc4.net/index.php?topic=51957.msg1135813#msg1135813
http://www.denoonsp.com/quick-turn-throttle.htm
http://www.kzrider.com/forum/3-carburetor/284429-external-carb-fuel-bowl-level-measuring-device

Now that this bike is complete, time to think about CB400F #5 and I started on my CB750K4 last night. No rest for the wicked....
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Dec 23, 2012, 13:29:30
Alright, snow is here and it is time to work on bikes. My matched sets of replacement Honda needles and emulsions arrived las week and I installed them in the original carbs for this bike (CB400F #4). The difference is night and day. PERFECT idle, no more idle hang and I was able to synch the carbs in less than two minutes. The bike has never ran or sounded better. It is going to be a loooooong wait until spring. A long and hard lesson learned: use OEM Honda carb parts.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2697-Version2.jpg)

I broke and cleaned the carbs (again) and while I was in there, I tossed out the original phillips screws holding the arm plate to the throttle valve and replaced them with hex head screws. It is much easier to get inside the throttle valve with a thin 2mm hex wrench than a screwdriver.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2890-Version2.jpg)

(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2885-Version2.jpg)
OEM Honda needle and clip (top), after market (bottom). Dimensionally they are very close but note the color difference.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2891-Version2.jpg)
OEM Honda emulsion tube on left, aftermarket on right. Note the difference in the needle seat design.
Others have reported the brass used in after after market carb parts are softer and wear quickly.

I cannot take credit for this idea, somewhere on my CB400f carb research I read about replacing main jet springs with a spring and clip (Thank you Davis96 http://forums.sohc4.net/index.php?topic=101803.msg1137530#msg1137530). My jet springs were in really bad shape, they are no longer available so I went with the spring set up and it works great.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2896-Version2.jpg)
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2897-Version2.jpg)

I will go over the bike one more time, re-tighten all the nuts and bolts, tweek the seat cover a bit, a good cleaning and then tuck her into her warm bed until spring. I will ride another 50 or so shakedown miles and then sell her. I think I am going to start on my other CB400F (#5) this week when my new seals and gasket sets arrive. I plan to strip it to the crank and restore it to stock factory condition and sell it too this spring. I'll do another thread for it soon. Happy holidays all!

Title: Re: Another Honda CB400F cafe racer
Post by: McMahon130 on Feb 03, 2013, 20:20:58
I just picked up a 1975 400F SS that I am hoping to build up.  It is in excellent running condition, but does need a little work.  My plans with it are to replace the front master cylinder as the brakes squeak; clean out the engine, carbs; redo the entire wiring; remove the electric start; repaint the tank; and do some minor cosmetics.  I am still getting caught up on this thread, but I came across your tank work, and I am curious where you got the Honda SS graphics.  Can you give me some insight on this please?
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Feb 04, 2013, 12:06:53
reprodecals on Ebay. From Canada, good quality. http://www.ebay.com/itm/1975-1976-Honda-CB400F-red-decal-set-/370522417345?pt=Motorcycles_Parts_Accessories&hash=item5644db68c1&vxp=mtr&_uhb=1
Title: Re: Another Honda CB400F cafe racer
Post by: McMahon130 on Feb 04, 2013, 18:39:39
Thank you! This is exactly it. 
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Apr 05, 2013, 14:57:10
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_4065_zps7aee6ca3.jpg)

Took the first ride of the season yesterday on my Triton and the first ride on this CB400F today. Wow, I love this bike and she is so happy. Charged the battery, fresh gas into clean carbs and she fired right up into a smooth idle. I forgot how good this bike sounds and moreover how fun it is to ride. I went out and stretched her legs, blew dust off, broke a few laws, but nobody got hurt. Gonna clean her up and sell her. This is going to be a difficult goodbye...
Title: Another Honda CB400F cafe racer
Post by: SONIC. on Apr 05, 2013, 16:10:13
Don't sell!
Haha
Title: Re: Another Honda CB400F cafe racer
Post by: Worst cb650 ever on Apr 05, 2013, 16:18:03
Yea Swan, can we send our problem child bikes to you and have you rebuild them to your level of quality?  ;D
Title: Re: Another Honda CB400F cafe racer
Post by: o1marc on Apr 05, 2013, 16:21:33
What will you ask for that bike?
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Apr 05, 2013, 18:20:19
Thanks guys, actually a friend dropped off a 72 BSA Lightning for me to go through the carbs, timing, chain, tires and hubs. I do not have a shop rate and do this soley for fun, but he was making hints about giving/selling cheap a 1966 Honda 305 he wants me to have, hmmmm, next project???

I would like $3800 for this CB400F. Mechanically sound, frame up paint, new spokes, tires, new seat, running beautifully etc. Way too much time getting the carburation perfect. The only issues are the front fender and a weird clear coat issue on the tank I am not happy with. I have not decided whether to go Craigslist or E-bay. Tomorrow.
Title: Re: Another Honda CB400F cafe racer
Post by: Worst cb650 ever on Apr 05, 2013, 21:34:52
I think we'd just like to see you do another build now that the Gold Star is coming to an end.  The 305 is a lovely bike that would make a nice restoration, I'd think.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Apr 06, 2013, 21:57:52
Thanks Worst. Thinking hard about the 305.

This CB400F is up for sale and I will let you know how it goes.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_4102_zpsbfb8b3b4.jpg)
http://minneapolis.craigslist.org/hnp/mcy/3732892913.html
Title: Re: Another Honda CB400F cafe racer
Post by: braveg on Apr 08, 2013, 12:48:33
Damn, if only shipping this bike to SA didn't cost as much as the bike I would buy it in a heartbeat! Crank up that price man, someone is getting it at waaaay too much of a bargain :o beautiful work, I have 4 of these babies in my garage in various stages of restoration and I know just how much work goes into doing a build of this quality, the new owner is going to be a lucky, lucky person.

Well bloody done!
Title: Re: Another Honda CB400F cafe racer
Post by: Maritime on Apr 08, 2013, 14:00:57
I sooo wish i had the dough to take this off your hands Swan, it is a super fair price for that bike! I want one badly, but I have no disposable income for it and won't for at least another 2 years. Maybe the next time you flip one I will be ready.
Title: Re: Another Honda CB400F cafe racer
Post by: NeightRG on Apr 08, 2013, 15:40:48
Renting the same workshop as Swan, I've had the privilege to watch this build (and plenty more of his work) very closely. Whoever buys this bike is in for a real treat.
Top Gear fans will know what I mean, when I say that the sound of that 4 into 1 exhaust with the repacked Dunstall style muffler really brings on "the fizz"
Not even my bike, and it'll be hard to watch it leave the shop.
Title: Re: Another Honda CB400F cafe racer
Post by: MotorbikeBruno on Apr 17, 2013, 11:15:04
Was looking through CL today and saw your bike. Amazing for sure.  I hope this goes to a good home, and gets ridden, if I had the cash I'd be all over this thing as I've ONLY heard good things about how they ride.  Good luck with the sale man.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Apr 18, 2013, 12:28:42
Thanks all. I have had several nibbles, but no bites yet on the sale. I may go to E-bay next.
Title: Re: Another Honda CB400F cafe racer
Post by: hondacycle on May 14, 2013, 23:04:17
Thanks all. I have had several nibbles, but no bites yet on the sale. I may go to E-bay next.
I'll be watching this build very closely... Closer than most. Looking good.

Hi my name is Norman.

 I am currently working on a 76' CB400F. My delima is, does this engine require 8 valve stem seals or 4? I noticed the intake valve guides are different from the exhaust valve guides. I have a genuine Honda Service Manual as well as a Haynes Service Manual. The Honda manual say's it requires 8. The Haynes manual say's it requires 4. If it  truly only requires 4, Which side do they go on intake or exhaust. Now I did attempt to install all eight, however when the seals are placed on the exhaust side the inner valve spring is rubbing on the valve stem seal. HELP!
Title: Re: Another Honda CB400F cafe racer
Post by: o1marc on May 14, 2013, 23:13:00
Thanks all. I have had several nibbles, but no bites yet on the sale. I may go to E-bay next.
I tried to pull up your ad but it says it was flagged and removed
Title: Re: Another Honda CB400F cafe racer
Post by: M. Wolfe on May 30, 2013, 18:16:32
I am having a challenging time getting my bike to idle correctly with individual K&N pod filters. There are dozens and dozens of threads online (Do the Ton, SOHC, Yahoo Auto Groups, et al) discussing this very problem and most say it cannot be done. It can be done and I have successfully run pods on three other CB400f's using stock exhaust, dropping the needle clip one notch and running 80 or 85 main jets. This bike has a repacked Dunstall replica muffler (which sounds awesome!), stock 4 into 1 header, 80 main jets, raised the needle one notch (lowered the clip, enriching the mixture to compensate for more incoming air) and a #38 pilot jet. I have quadruple checked timing, ignition, valve clearances and confirmed there are no vacuum leaks. The carbs, floats levels all passageways etc have been meticulously cleaned several times and set to spec. I am at 700 feet elevation and it is generally in the 50's farenheit when I am doing test runs and plug chops. The bike runs extremely well above the idle circuit, but down low it idles high, hangs, then drops down to a too slow of an idle. This has nothing to do with mechanics of the carbs (slides, springs, throttle cables etc) I believe one or more of the pilot jets are fouling, causing the idle to drop. This has made synchronizing the carbs at idle difficult.

Well, last night I did a series of compression tests with the engine cold, wide open throttle (WOT), cold with a bit of oil squirted into the cylinders and WOT and after I ran the bike around for awhile. Cylinders 1,2,3 were consistently in the 130's psi on all tests with my cheapie compression gauge. Cylinder #4 was 75 psi cold, 85 with oil added and 80 psi after running, telling me there was a leak in the valves, not the rings or cylinder on #4. I checked the torque on the cylinder head and all bolts were tight and to spec. There are no air leaks around the cylinder head or gasket area. So, off with her head-I ripped her down to lower end last night. I knew the chamber of cylinder #4 had some pitting and corrosion which came with the bike. I did lightly lap the valves with rough and fine compounds when I rebuilt the motor.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2062-Version2.jpg)
#4 on the right, note the pitting.

What I discovered was some of the pitting and corrosion was also in the inlet valve seat of #4, allowing for a slight leak, causing the low compression reading. In a dark room, I shined a strong led flashlight (http://www.robustbuy.com/led-lighting-gadgets-led-flashlights-c-505_1027_730.html) into the inlet and exhaust ports and discovered two tiny light leaks on the inlet valve seat, the culprit of my compression leak. If I did it right the first time, I would not be doing this now.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2064-Version2.jpg)

I am meeting with a machinist friend today who has the proper sized valve seat cutters. Hopefully, we can lightly cut the valve seat in order to remove the two small areas of pitting without having to replace the whole valve seat (time and $$$$).

As long as I am at it, I am replacing the kick start quadrant with a slightly used one with better splines than my original.
(http://i170.photobucket.com/albums/u272/66triton/CB400f/IMG_2057-Version2.jpg)

With 4 cylinders of even compression I should have an easier time dialing in and synching the carbs and fixing the idle problem. I'll post my results, stay tuned....

I am a new biker and i know that is not easy to get fixed on your bike.. hehe.hehe.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Jun 16, 2013, 17:59:29
I do not want to deal with E-bay. I rode it yesterday and this is such a great bike, but I need to let it go. Relisted it on Mpls Craigslist:
http://minneapolis.craigslist.org/hnp/mcy/3875009767.html
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Jul 06, 2013, 11:36:31
Almost sold her today, but the buyer backed out, he liked it but was not sure what he really wanted. No hard feelings and I want to make sure the next owner is 100% satisfied before they plonk down cash. I will call back the next person in line to by it.

I installed a Dyna electronic ignition and the bike has never ran better. Wow, it really makes a difference and I will use EI on future Honda builds.
http://minneapolis.craigslist.org/hnp/mcy/3875009767.html
Title: Re: Another Honda CB400F cafe racer
Post by: Maritime on Jul 06, 2013, 21:40:44
Damn swan I hope you sell it to someone who wants it as bad as I do.

Sent from my MB525 using Tapatalk 2

Title: Re: Another Honda CB400F cafe racer
Post by: redlabel on Jul 26, 2013, 05:49:37
Hi Swan!
Love the build and quality of your bikes!
Can you get original Honda jets in the correct size if you run pods and aftermarked exhaust?
I have been looking at these kits from Sigma on e-bay but not sure about the quality.
http://www.ebay.co.uk/itm/Honda-CB400F-CB400-CB-400-Four-Type-F-F2-Carburetor-Carb-Stage-1-3-Jet-Kit-/230962601062?pt=Motorcycles_Parts_Accessories&hash=item35c6719c66&autorefresh=true
Title: Re: Another Honda CB400F cafe racer
Post by: Felfriast on Jul 26, 2013, 06:08:42
Nice work!
Title: Re: Another Honda CB400F cafe racer
Post by: redlabel on Jul 26, 2013, 10:27:53
Hi Swan!
Love the build and quality of your bikes!
Can you get original Honda jets in the correct size if you run pods and aftermarked exhaust?
I have been looking at these kits from Sigma on e-bay but not sure about the quality.
http://www.ebay.co.uk/itm/Honda-CB400F-CB400-CB-400-Four-Type-F-F2-Carburetor-Carb-Stage-1-3-Jet-Kit-/230962601062?pt=Motorcycles_Parts_Accessories&hash=item35c6719c66&autorefresh=true

Hi again..
Found the partnumber for the Honda Slow jets in #38. It's  99124-076-0380 so now I only need for the mains.......maybe a size #85 on the main.?
Title: Re: Another Honda CB400F cafe racer
Post by: redlabel on Jul 26, 2013, 10:32:45
Hi again..
Found the partnumber for the Honda Slow jets in #38. It's  99124-076-0380 so now I only need for the mains.......maybe a size #85 on the main.?
......and the main #80 har partnr.: 99202-601-0800
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Sep 26, 2013, 22:54:33
Sold, (finally) to a cool guy in the Twin Cities. Took him out for ride along the river and I know by the smile on his face it was going to be his. I shall be starting CB400F restoration #5 next month and start another thread. Thanks all!
Title: Re: Another Honda CB400F cafe racer
Post by: fenixv8 on Aug 15, 2014, 12:35:43
Dont mean to intrude on this thread but i am in a bit of a bind and this thread is the onlyone that I can find that related to my issue. I bought a 1977 CB 400f and it had a really free flowing exhaust and shitty pods on it.
It was running rich all around plugs fouled.  I ordered a keyster kit (before reading this thread)  opened the carb up and realized a keyster kit was probably installed on it. I replaced all the internals of the carb with stock honda parts now and it still is running way to rich.
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Aug 17, 2014, 16:16:20
Do you still have a free flowing exhaust and shitty pods on it? If so, you will need to make adjustments to accommodate them.
Title: Re: Another Honda CB400F cafe racer
Post by: MotorbikeBruno on Aug 31, 2014, 17:02:09
Dont mean to intrude on this thread but i am in a bit of a bind and this thread is the onlyone that I can find that related to my issue. I bought a 1977 CB 400f and it had a really free flowing exhaust and shitty pods on it.
It was running rich all around plugs fouled.  I ordered a keyster kit (before reading this thread)  opened the carb up and realized a keyster kit was probably installed on it. I replaced all the internals of the carb with stock honda parts now and it still is running way to rich.

If you have stock parts...and you are running rich, it's more likely a setting you have missed/screwed up  ;)  I'd assume float height and mixture screws as the first culprits. And to check the slide needled to verify they haven't been set far too rich (clip towards the BOTTOM of the needle if it has the adjustable clips)

Swan, I saw your ad on CL for the 400. She's a beaut.
Title: Re: Another Honda CB400F cafe racer
Post by: Rogue on Sep 01, 2014, 04:08:03
Great thread. Love the detail. Can you tell me what gasket kit you used?
Title: Re: Another Honda CB400F cafe racer
Post by: swan on Sep 07, 2014, 12:48:48
I used a Vesrah gasket kit. So far, so good.
Title: Re: Another Honda CB400F cafe racer
Post by: bonbons on Dec 18, 2016, 15:55:01
Happy I stumbled onto this as I'm on a slow start with a '75 CB400F rebuild. Great work here!
I especially like the "NOT YOURS" tape measure B-)
Cheers!