collapse

www.dimecitycycles.com

www.cognitomoto.com

https://www.townmoto.com/collections/vanson-leathers

www.speedmotoco.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.lostapostlejewelry.com

www.sparckmoto.com

www.pistonsociety.com


Author Topic: Another Honda CB400F cafe racer  (Read 63824 times)

Offline swan

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1004
  • Kickstart, shift on right, drum brakes and spokes
    • 1962 BSA Gold Star barn find restoration
Re: Another Honda CB400F cafe racer
« Reply #30 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!
1966 Triton cafe, 1962 BSA Gold Star DBD34, and 1966 T120 Triumph Bonneville.
BSA Gold Star barn find restoration
1975 CB400F Cafe Racer build
1966 Triumph Bonnevile restoration

Offline JustinLonghorn

  • DTT SUPPORTER
  • *
  • Posts: 6677
  • No Purple Hearts, No Blue Ribbons
Re: Another Honda CB400F cafe racer
« Reply #31 on: Oct 18, 2012, 12:04:10 »
Very clean, sir!
I'm going to eat your brains and gain your knowledge.

Into The Sunset, CB750 build

TT500 the Animal

Offline juan@crqcycles

  • Posts: 234
  • Not a lot of cafe's down here in Mexico...
    • CRQ Cycles
Re: Another Honda CB400F cafe racer
« Reply #32 on: Oct 18, 2012, 14:01:36 »
Beautiful!
Please upload the video!

Offline swan

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1004
  • Kickstart, shift on right, drum brakes and spokes
    • 1962 BSA Gold Star barn find restoration
Re: Another Honda CB400F cafe racer
« Reply #33 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.
1966 Triton cafe, 1962 BSA Gold Star DBD34, and 1966 T120 Triumph Bonneville.
BSA Gold Star barn find restoration
1975 CB400F Cafe Racer build
1966 Triumph Bonnevile restoration

Offline john83

  • DTT SUPPORTER
  • *
  • Posts: 1719
Re: Another Honda CB400F cafe racer
« Reply #34 on: Oct 19, 2012, 21:57:33 »
That's a fine looking scoot there, sir.

Offline swan

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1004
  • Kickstart, shift on right, drum brakes and spokes
    • 1962 BSA Gold Star barn find restoration
Re: Another Honda CB400F cafe racer
« Reply #35 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.






1966 Triton cafe, 1962 BSA Gold Star DBD34, and 1966 T120 Triumph Bonneville.
BSA Gold Star barn find restoration
1975 CB400F Cafe Racer build
1966 Triumph Bonnevile restoration

Offline andycafe

  • Posts: 1173
  • Northern Suburbs, Melbourne Victoria, Australia
Re: Another Honda CB400F cafe racer
« Reply #36 on: Oct 22, 2012, 08:19:07 »
Sweeeeet ;D

Offline Wangofree

  • Posts: 573
Re: Another Honda CB400F cafe racer
« Reply #37 on: Nov 02, 2012, 16:45:10 »
. . .  and I have humbly accepted a nomination for Bike of the Month for this beast.



Rightly so.  Fantastic work.  Extremely impressive.
"I got a fever, and the only prescription is, more cafe racer parts"!

Ongoing CB360 build
http://www.dotheton.com/forum/index.php?topic=43522.0

Suzuki GS550
https://www.thegsresources.com/_forum/showthread.php?253794-Bringing-a-78-GS-550-back-to-life

Offline 3DogNate

  • DTT BOTM WINNER
  • *
  • Posts: 1206
  • "You Meet the Nicest People on a Honda"
Re: Another Honda CB400F cafe racer
« Reply #38 on: Nov 02, 2012, 17:57:44 »
I like it... those headers look so cool. Clean build... be proud.

Offline swan

  • DTT SUPPORTER
  • *
  • DTT BOTM WINNER
  • *
  • Posts: 1004
  • Kickstart, shift on right, drum brakes and spokes
    • 1962 BSA Gold Star barn find restoration
Re: Another Honda CB400F cafe racer
« Reply #39 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.

#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.


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.


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....
1966 Triton cafe, 1962 BSA Gold Star DBD34, and 1966 T120 Triumph Bonneville.
BSA Gold Star barn find restoration
1975 CB400F Cafe Racer build
1966 Triumph Bonnevile restoration