1 is Fun, 2 is Difficult, 3 Must Be EASY- CB400F Racer, CB750 Cafe & XS360 Xplr

So here is the theory: building one motorcycle is fun but building two at a time is difficult. Therefore, by all logical thought, building three at a time MUST BE EASY. I see no flaw in this theory.

The three bikes are:

- A 1976 Honda CB400F vintage race bike that is being prepared for AHRMA Formula 250 class duties. The plan is to have it completed for the Barber Vintage Festival in October.

- A 1977 Honda CB750 which is an incredibly fast machine that is being converted to a righteous cafe racer. The theme is black, on black, with some more black.

- A 1977 Yamaha XS360 cream puff that will begin its new life as a two-up all road moto. I'm calling it an "Explorer". Whether its the urban jungle, a twisty ride through the mountains, or a dirt single track, this bike can take you and a friend there in style.

I decided to cover these all in one build thread (if that is allowed?!?) since the work will be flipping from bike to bike as each progresses at different stages.

The race bike needs to be done ASAP for testing and then racing at Barber in the AHRMA event. I have a backup race bike (the CB350 in the background) just in case fate steps in.

The CB750 is being built for a friend. He has been begging for a 750cc cafe racer but I have refused. I have always found the 750cc Hondas to be too powerful for the brakes and chassis, but this later bike has the dual front discs, trailing third disc and a longer swing arm. This should make it safe. His only requirement is that everything be black like his special edition G-wagen. We'll see.

The last bike is going to be the most fun- the 1977 Yamaha XS360. I love building and riding righteous cafe racers. Problem is that they are traditionally a one person moto. Whenever a passenger is involved that precludes any of the Ton-up machines and we use one of the stock 70's machines- not that there is anything wrong with that. I looked at buying a new Triumph Scrambler, a Triumph SpeedTriple, a Ducati Hypermotard and a Triumph Tiger. They all looked big and heavy (except for maybe the Hypermotard) and were too cookie cutter for bike night. I decided to build a two-up, go anywhere and look awesome doing it machine. Something that could be taken out for dinner, driven through the mountain twisties, or go exploring on gravel/dirt road. It would be light, fun and have low/hidden pipes that keep legs and ankles from being burnt.

With the long weekend I was able to disassemble two of the bikes. I'm kind of cheating since the CB750 was taken apart previously while a custom fiberglass cowl was made.

I summarized the disassembly into some slideshows.

The CB400F was first up. Nothing major except the engine is not dry sump like the CB750 so the oilpan, pickup and breather need to be taken off to get it out of the frame. Not the best design, and a may make a modification to the frame with a removal section to alleviate this in the future. Need to check the rulebook since the AHRMA committee doesn't like improvements.

http://youtu.be/d9Hlgz5icPU

The Yamaha XS360 is an interesting bike. The frame looks like an RD at the front and a XS650 at the rear. The engine looks to be closer to a modern dirt bike than the Hondas of the same era. I'm not too sure about the forks. The guy that last worked on them wasn't too sure either apparently. They were about a 1/4-inch offset to the right which he fixed by shimming the front fender over. Right-O!

So the bike hasn't been run for about four years and was stored (abandoned) for that time in a sandy field under a tarp. It was covered in what I call New Mexico Grunge. Its a combination of oil, a little water, blowing sand, then a little water, blowing sand, repeat until a thick caked layer exists. Then bake it for several years where it turns to a hardened translucent substance like amber. It took quite a few gallons of product and four hours with the pressure washer to get most of it off.

Before staring the build I decided to see if the bike would at least lends itself to starting. The cylinders had checked out for both compression and the scope should good crosshatching. I knew the carbs were junked up with the NM Grunge but I wanted to check for spark and timing. This led to several hours of electrical trouble shooting. I think I traced the problem to a connector that has had the wires reversed in it and a broken kill switch. Several times during this exercise I was tempted to just stop since none of the stock parts will be reused but i wanted to make sure the engine "ran" before attempting the transformation. Well, after bypassing the electrical with a simple harness to feed 12V directly to the ignition, and some 118 octane jetted into the carbs, the engine sprang to life. Mission Accomplished.

This bike could easily be converted in a righteous cafe racer. I even fitted a cafe seat cowl from a Honda CB360 on it to check. However, the one-up seating means no date night with the wife or quality time with my daughter. I decided to trial fit a scrambler seat, raise the footpegs for clearance and mount a set of supermoto bars to see how it looked and felt. It was sublime.

These parts won't stay but the concept was born- the XS360 Xplr.

http://www.youtube.com/watch?v=FkBpxs-gcwU&feature=colike

As I mentioned, the CB750 was previously disassembled and used for a how-to session on building a cafe racer seat/cowl for a few friends.



Almost everything will be matte black. I was planning on a big bore kit for the engine, but its condition is so sweet this may be a waste. I have a special speed fix planned if all goes well.

3 projects at once...you sir, are a madman! haha...definitely watching this space. I'm in.

Green199 said:

3 projects at once...you sir, are a madman! haha...definitely watching this space. I'm in.

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I am hoping that it plays out correctly and when i get stumped or get to a natural stopping point like paint, I can move onto the other projects.

I was able to get the Yamaha completely disassembled and powerwashed last night. I took a few critical measurements so I could order a new cool set of tires. I also have a few parts that have dribbled in or I have been hoarding that I'll post later.

http://youtu.be/MZ64HwOnoyk

Took today off to put some miles on a motorcycle before the Track Day this weekend. Apparently I need 600miles before the rev limiter will come off I was only able to do about 200miles before the rain came.

Picking paint colors in the morning. Thinking something crazy...

I was able to find a great dual piston caliper for the CB400F and I'm upgrading the front end to a bigblock GSX1100W. I plan to upgrade the internals to gold valve emulators and hopefully external preload adjustment. I have a set of excel allow rims but getting the spokes in time may be an issue for next weeks race. Might need to run the stock steelies for now.

For color I was looking at a Z06 Corvette in Inferno Orange metallic.



Almost forgot, I tried the Pine-Sol trick on the XS360 carbs and its about a 75% solution to varnished carbs. Nothing replaces hard work with a wee lil brush. I had planned to powdercoat and polish the individual carb pieces but I have another trick I want to try first...

As a fellow xs360 owner, I'll be watching this. Also interesting colour choice, cl360's of the same era had a colour option like that.

Spent the last two days at the race track....still an excuse but a pretty good one. Stayed upright but switching from an open class Mac nine, to SuperMoto and then Vintage was weird. Fun, but weird.

Picked out the paint but restricted my choices to ready made colors for easy color matching as opposed to custom colors or candies. Well, maybe i splurged a bit. The metallic and pearl additives have sure gone up since Japan had their nuclear meltdown.

I did purchase a new pipe bender. Since I need to craft an AHRMA-legal swing arm and some frame bracing, upgrading from the manual bender seemed like a good idea.

Bronze swing arm bushings will need to be machined but I'll save the through bores until after installed in the swing arm.

Wow... Ambitious. I like it! Any chance you'll be disposing of the stock 360 tank?

No, I love the tank but I have an extra. Was going to use it on the RD but the RD mount is different.

Figuring out the CB750 seat tonight. I have the custom oil tank done but the seat is causing issues. Trying to decide if I cut the rear part of the frame off and replace with a new section. I also have some foaming and fiberglass work to do to get the seat to flow into the gas tank. I may do it in the seat cover to give some ball cushioning when you clamp down on the dual disc brakes.

redwillissuperman said:

No, I love the tank but I have an extra. Was going to use it on the RD but the RD mount is different.

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Gotcha. Well if selling either becomes an option, please let me know.

Stupidly had a Costco hot dog for lunch and spent the rest of the day regretting it.



Was able to fool around with fiberglass long enough to make a quick idea for the rear seat cowl. It's still tacky.

I'm realizing that in order to hide an 8-cell battery for the CB750 pig starter, that a bigger rear sear cowl in needed. I'll connect it forward to the tank tomorrow and see how it looks.

Long night watching fiberglass dry...not very exciting. the Cb750 seat should be dry tomorrow!

Stripped down the CB400F tank for paint. Decided to not re-use the race seat but went for a longer CR seat to fit my large size. Waiting for the new frame to arrive. Will strip the engine tomorrow for power coating. Need to order some race tires, thinking Diablos or Conti race.

The XS360 is languishing since I've become obsessed with the carbs. Should have stripped the engine down on it tonight. Played around with the dual sport tires. Once the wheels get tried and powder coated I can mount the tires and see if they fit!!!!

XS360:
Here is me playing around with the XS360 rear tire. Its a 120 which might be to wide for the little frame. If this was a XS650 then no problem. I might order a 100 and deal with the reduced "manliness".



CB750:
Watching fiberglass dry.....yes, I know its way to long and a waster of materials. But whenever I cut it short, when I apply the resin, my brush stroke pressure curls the edges around. Tonight I will combine the from and back sections once I set the final length.


CB400F:
The stock seat has always been too short and wasn't snug to the tank. Thinking of extending the front to meet the tank and maybe giving it a rise at the lip. I also tried the Hot Wing Glass seat I have had laying around forever trying to find a home. I should just put it on a CB360 and be done with it.

Man, you're really motoring along. Pun intended.

I had to post these. It makes perfect logical sense that when you take 400cc of displacement, divide by four and the stroke, that you end up with Teeny Weeny Micro-Meeny Pistons:





Will be sending these out for ceramic crown coating and piston skirt slipper coating.

shamus said:

Man, you're really motoring along. Pun intended.

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The thing is, I'm actually (helping with) building two other bikes, in addition to the three here. My daughter's dirt bike and my wife's racebike which she dropped on Sunday (sorry dear)....

The wife's race bike before "The Incident".... :-[