• Enter the March CB750 Supply gift certificate giveaway! It's easy... Click here, post something, and you're entered into the drawing!

Which carb kit?

noyloj

CB750 Custom CR project
Messages
3
Reaction score
0
Points
1
Location
United Kingdom
Hi there
I have recently bought a US import CB750 custom in the UK, it's a non runner although it turns over. I want to do a complete carb rebuild before I attempt to fire her up, will any carb kit for a DOHC CB750 work or am I looking for a specific part number? I'm not sure they sold the 750c in the UK...
 
As long as for '79-'83 DOHC they are pretty much the same. Make sure 750 though, the 900 and bigger are the same too but small parts in kit can change like jetting sizes and if aircuts are supplied then aircuts are different on the 1100. The 750s all use same kit whether C or F, or K or, etc...................

I should point out that Euro spec carbs do not have the US spec EPA mandated accelerator pump, you may need the diaphragm, shaft seal and o-ring for it on the #2 carb.
 
Last edited:
Hi Noyloj!

I'm new to this as well and definitely not an authority on any of it. But, I've read a lot of forums and gained a lot of insight from other members. You can look at the side of the carb for the model. If stock, it should be a vb42a. Verify that first.

If that's what you have, kits can run from $30 USD to $190 USD. I've see a lot of complaints that the cheaper kits don't have the parts that fit "quite right" or missing some key components. Some people rebuild them with all new parts while others never change anything, but merely clean what's there. It'll depend on condition and your attention to detail.

With my rebuild I had to purchase new float bowl gaskets, float drain screws, rubber slow jet plugs and an o-ring for the accelerator pump amc49 mentioned. (If you need this and it doesn't come with your kit let me know or look at my "for sale" thread on his forum )

Another thing that seems to be repeated throughout is that it's highly unlikely your carbs are why it's not running. It may be a failure point for sure. But, before going all wild and crazy with jetting etc., make sure you've adjusted the cam chains and checked/adjusted the valves. There's lots of posts and videos of this information. And get a service manual! (Also found online for free)

My personal "not siezed, not running" bike progress is as follows: clean tank, clean Petcock, change fuel line and add filter, clean carbs, adjust cam chains and valves, change oil filter and plugs, new battery and see if it will run before proceeding. If all goes well, check charging system and compression. Once all that's done, adjust for running smoothly. Then move on to drive train (clutch plates, chain, sprockets etc. ) and brakes. Get it running, get it moving, get it stopping. Is this the right order? I don't know, but time will tell. Best of luck!

Also, definitely download seang's carb manual and read it several times before getting into them. You can search for it or maybe someone will chime in with a link.
 
Thanks for the advice...I will try and just clean up the carbs as recommended. I have already downloaded the carb manual and will at least try and get basic carb kits (in case I break something) and stainless set screws before starting...
Incidentally were the later carbs fitted to the '90s CBs better/more reliable?
 
Back
Top