My CB 836

[QuebecBob]

Thought maybe this might interest you. I am new here. Each winter I build some kind of café racer out of a CB750. Usually I sell them in the spring but I can't sell this one. I like it too much. The motor is a combination of different SOHC years with a big cam and Wiseco pistons, with the premium Cycle X gasket kit. The biggest challenge around the motor was finding the right carb jettings, matching to different pipes and playing with different intake breathers. I tried velocity stacks but they are just too finicky for my tastes. The pipes you see here are Kerker 4:1 headers with an aftermarket can from Wolf.

The frame is from a '74; the front and back end are '96 GSXR Suzuki, swing arm is from the '70's Harley wheel conversion for CB's; tank is Benelli 360; I made the seat and side covers and did the rattle can paint. Luckily, my best friend is a great machinist. He machined a lengthened bolt in the headstock to capture the shorter steering stem of the GSXR and built the back axle. Aligning the sprockets was the build's biggest challenge. Rear sprocket is offset 10mm, front is also offset 10mm with an interior dummy sprocket to give the needed spacing. There is about 3/16 of an inch space between the chain and 180mm rear tire edge, but that's enough if you keep everything aligned.

I lucked out on a lot of things on this build. Spied the GSXR stuff sitting on a pallet at a dealer and paid $350 for it all, including the forks, brakes, master cylinder, wheels, tires and clip-ons. (I thought I was the first guy to do this CB/GSXR retrofit; didn't know a lot of people do it.) A bud sold me the tank for $100 and the 2 of these mufflers from another bud for $100. Healight was $20 at a swap meet; bought the Tomaselli rearsets on this site and made the mounts myself. The rear brake mount was a bit of a geometry puzzle (brae actuator/taillite actuator and then the lever itself) but I enjoyed it. I buy scrap CB750's and so have a lot of parts to mix and match. Saves chasing after stuff, especially on Sundays!

I've put about 600 miles on it so far and love it, especially now that I have the carbs properly adjusted. It attracts a lot of attention and is surprisingly comfortable. It is really worth the investment to have a professional upholsterer. Hope you enjoyed this little summary. If you have questions I would be happy to respond. I have pictures of the entire build if it can help anyone.

[Re-run]

I'll tell ya, that is a really sweet bike. It has a really good mix of new and old to it. Beautiful lines for sure.

You might want to get ready though, there might be a few requests for those side covers! Oh, and a more in-depth write up of the front and rear swaps you did.

[QuebecBob]

 
Thanks. The side covers are simply 16gauge tin. I tried a lot of different mediums and looks and settled on these. The bumstop is the rear portion of an old CB gas tank. The GSXR rear wheel slides right in to the Harley wheel swing arm once you do a bit of light grinding. I welded a couple buttress supports after grinding just to be sure. As I say, the front end is pretty straighforward, once you determine how to accomodate the shorter steering stem of the GSXR. The diameters of the stems are identical. I found the GSXR front fender too modern and cut back a CB one instead. It's easy to do with simple rivets and you can play with different looks easily. The most interesting feature of these builds is the sitting back and observing overall look, stance, proportion and paint. You get to really have your own individual look. Be willing to re-do things until you really like the result.

[TOOLS1]

Very nice bike. I am curious about the swing arm. You say it one for a Harley wheel, but it looks just like a CB 750 swing arm. I know a lot of guys will put a 16" rim on the Honda hub, and refer to it as a Harley wheel, is that what it was, or is it something different?
TOOLS

[QuebecBob]

You are right on. CB hub laced to a wider Harley rim with short (now hard to find, I am told) spokes. The swingarm is a CB but widened. My understanding is they were after market at the time. I have a few of them. I guess they were popular in my region. Or were they popular everywhere?

[TOOLS1]

The 77-78, and the A model swing arms were wider then the 69-76 models. They were also an inch or so longer. I have never heard of a special aftermarket swing arm for the CB to use a Harley wheel. And there would not be any need for such a swing arm if you were still using the Honda hub. As for the spokes, you can still get them, but they are a little pricy now. I myself like the DOHC swing arm. It is the same width as the 77-78, but is even longer. Looks really cool on a SOHC. It moves the shock mount to the rear, and lowers the bike.
TOOLS

[QuebecBob]

I appreciate this knowledge. It explains why there are so many of these swingarms. I was working off of folklore. Thanks.

[Re-run]

We need to get more documents about the various cb750 mods that were/are commonplace and how they are done. For example, the dual dick mod as well as various others.

[sgtslag]

I see you added an oil cooler (thermostat, or on all the time?), and a temperature gauge.  Did you also replace the filter with a spin-on for ease of maintenance, or ?...  What oil temperatures does it run at with the over-sized pistons and what-not?  Just curious.  Thanks for sharing.  Cheers!

[TOOLS1]

Re-run wrote

We need to get more documents about the various cb750 mods that were/are commonplace and how they are done. For example, the dual dick mod as well as various others.

"dual dick mod"?
TOOLS

[Re-run]

Oh, you haven't added that mod yet? Oh that's too bad!

[QuebecBob]

Hi. Was offline riding a few days. I added the oil cooler as I thought the cylinder walls pretty thin after the re-bore. But what you see there is actually an oil pressure guage and not a temperature guage. I was discussing lately with a friend how I actually think the oil pressure guage the most important guage on a bike. It ought to replace the tach in terms of prominence, in my book. You can always hear your revs but you can't tell your oil pressure. Food for thought...

[TOOLS1]

I find it hard to watch an oil pressure gauge, and pay attention to where I am going, and all the other things involved with riding a bike. By the time you notice the gauge showing a loss in oil pressure, you have already lost your engine. The light is more noticeable when it comes on, however the best warning system would be a buzzer, or better yet a system that automatically shuts off the engine. Also I have see engines fail because of the connections failing on the lines/fittings for the oil pressure gauge.
TOOLS

[QuebecBob]

You're right on all counts. I also ride a Norton Commando and when it is hot and at speed, it often will display practically no oil pressure at all. I guess what I am saying is, by habit, in the same way that we probably don't realize how many times a minute we check our review mirrors, we check our tach and speedo with great frequency, when other monitors would actually warrant more attention. I always build in a dashboard light for my signal flashers and too often realize I have been driving for a few minutes signalling an unintended turn. So the old lady at the interseciton in front of me says to herself, "He's turning on to my street, so I guess I can pull right out onto his street". Now that is critical information!

[Hoko]

TOOLS1 wrote

The 77-78, and the A model swing arms were wider then the 69-76 models. They were also an inch or so longer. I have never heard of a special aftermarket swing arm for the CB to use a Harley wheel. And there would not be any need for such a swing arm if you were still using the Honda hub. As for the spokes, you can still get them, but they are a little pricy now. I myself like the DOHC swing arm. It is the same width as the 77-78, but is even longer. Looks really cool on a SOHC. It moves the shock mount to the rear, and lowers the bike.
TOOLS

Tools, what year DOHC swingarms can be used on the 77, 78 hondas?  Would that apply to Super Sports too?

[TOOLS1]

I have been told, but cannot confirm that the 79 models are a direct bolt on. All the others (80-83) need some modifications. You need to trim 1/4" off each side where it bolts to the frame, and trim 1/2" from the space inside it. Then drill out the holes in the frame to 5/8"
TOOLS

[Hoko]

TOOLS1 wrote

I have been told, but cannot confirm that the 79 models are a direct bolt on. All the others (80-83) need some modifications. You need to trim 1/4" off each side where it bolts to the frame, and trim 1/2" from the space inside it. Then drill out the holes in the frame to 5/8"
TOOLS

Thx