cb750 overbore Q

[halftide45]

Hey y'all,

Just a quick question:
I have a 1982 cb750k which i'm overboring to fit cb900 pistons. I bought an aftermarket cb750 head gasket back before I knew I was doing the overbore, will it still fit after the rebore? the bore is increasing by 3.5 mm.

thanks!

 

[Tune-A-Fish]

piecemeal or kit? did you trim the case or plan to? The gasket wont work, you need to look for an 850-900+ big bore gasket.

 

[halftide45]

Its from a top end rebuild kit, so at least most of the other gaskets will still work. I thought as much, thanks for the info though!

 

[Tune-A-Fish]

Sure!

I may be misunderstanding... new cylinder sleeves? if yes... I do suggest you measure the sleeves at the base and the top case to be sure they will slide in. Not frustration like getting all those rings stuffed to find the sleeves wont get past the case.

 

[halftide45]

Nope, same sleeves. Just an overbore.
Yikes, I hope you don't know that from experience...

 

[Tune-A-Fish]

Nope, same sleeves. Just an overbore.
Yikes, I hope you don't know that from experience...

No, but I am familiar with big bore sleeves and having to modify the cases and even the piston skirts on some motors with squirt jets that spray the bottom of the piston with a jet of oil to lube and cool the wrist pin. Big bores with stroker cranks can interrupt the heads/valves too so ya know... Was just looking ahead of the game.

 

[coyote13]

Believe you'll find the proper head gasket about 1/4 of the way down the page, part #c8004. Works for 890-950cc overbores.

http://www.dynoman.net/engine/gaskets-cometic.html

 

[halftide45]

I appreciate it!
I was actually looking into resleeving instead of boring for a while. I got donated some cb900 pistons though, so it ended up being cheaper to overbore. And hey, a few more cc's can't hurt. Now I'm glad I didn't have to deal with the extra gotcha's.


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