cb900 compatibility

[Butcherblock]

Hey guys, a cb900c came up on craigslist as a parts bike, and I was wondering the compatibility with the  dohc750's. I noticed that the 900 carbs are 32mm, 750 are 30mm.  If the intake ports  are the same size, then I would grab the boots as well.  Might net a small HP increase. Anyone ever do this?
I am aware of the Cam swap as well. Probably try and score that too.
Thanks in advance!

[shinyribs]

Is a 900C the one with the weird 10 speed tranny's?

I'm still learning the DOHC bikes,but I do know a little just about the one I have.

Mine has a 750 case,jugs and head. We all know the 900 cams will fit in the 750 heads. So that will swap.

Mine has 900 rods on the 750 crank. They are a tad longer and require a cylinder spacer to work,but are supposedly stronger and swap in.

My 750 head is using 900 carbs right now. The boots look stock and un-modified,but since I didn't do the work I can't promise that.

900 transmissions and clutches will swap into a 750 case. Not sure if there is any advantage other than maybe a strength gain. I don't know if there are ratio differences between a 750 and 900.

The guy who built my bike had a 900 head on a 750. So that will swap,too. He also had a CB100 that was destroked (using a 750 crank) and had bored 900 jugs on it. Displacement came in somewhere around 930-ish. Seems wrong,but he was racing it and keeping the engine between 12-15k rpm. So apparently a bunch of this stuff will interchange.


And,I dont know this for fact,but if a 900 head will fit on 750 jugs...does that mean that 900 jugs would fit on a 750 case? If so that's be an easy big bore kit! It won't have the stroke of a 900 so I'm not sure what cc you'd end up at.

That's all i got buddy. Hope this helps somehow.

Oh,and the exhaust from any DOHC will fit any other. 750,900 or 100.

[Truck]

Yeah, the 900c had the snd tranny. However as far as I've been able to research a 900f engine is swapable with a 750 frame.

[Johnnylevi]

thats correct, but you will need all the mounts as they are different, as far as swapping the jugs if you do that I think you end up with an 815cc...