Topic: Boring 1976 cb750 - specs for carbs, jetting, etc

[SKOL]

I'm starting to do some research about boring my 1976 cb750. I was just hoping to hear from some folks who have bored their motors out, what size did they go to? Did they change carbs, jets, exhaust headers, cams? New to the forum, and new to this level of mechanical work too. I know if I bore my motor, subsequent parts of the motor needs to be changed or adjusted for the increase in cc's. Any forum threads about this already posted?

Thanks

[Bill/BentON Racing]

Lots, welcome. From 736 ,next besides 1st, 2nd, 3rd and 4th overbores, were 811cc, 812, 823, 836 ( most popular one)  to 73mm 1062cc, but usually called a 1080 kit. 900, 915, 970 all popular also, even 850 and 888!  Check out Wilbur's threads,  Madmtnmotors,  G'luck,  Bill

[PeWe]

Street use?
836 most common. You'll need more reinforcements like better rods if going bigger with a hot high revving cam.
Bore the std cyl to 65mm (836), port the head with bigger in valves 33.5mm. Cam DP295 or similar, race valve springs.

Use std carbs and your CB750 will be very fun and useful!
I should start with 130 mains, std pilots and needles 1 step richer (3:rd notch from top). (pod filters)
Std airbox or pods make difference in jetting and flow.

If you choose the cheap 836 kit with almost no valve pockets, forget hotter cam (and the HP with it) No meaning to do any port job either... except for the fine tuning of chambers and ports described in Hondaman's book

[edwardmorris]

I'm currently working on a big bore street/road racer with an 836 engine. There are several options based on your budget. Mine isn't particularly large, just a little above average because I have a strong disklike for having to redo things. You can follow along with the build if you wish (see link in my sig for K3). In the end, it depends on what exactly you are looking for. A good performance build? Can't go wrong with Mike Rieck and all the work he does. A basic engine rebuild just to have it running? Hondaman's book covers things in incredible detail to DIY. If you don't want to DIY and not looking for a HiPo build, you can have Hondaman/Mark do the work too.

[Big Jay]

836 is the most popular we have a complete kit SSR836 that has the piston kit, cam, valve springs and studs. http://cbrzone.com/sohc.html.  You may find the head needs service too, so check out this link.