TOPIC:

does anyone know the service specs for a 77/78 750 block
im intending to use one for a 1977 kz650b-1 /810cc project and need to know the bore specs so i dont buy a pice of junk block!
i got cams (83gpz750) lined up after the holidays, so now i need find a block in good shape to start it off!!!!

A 77-78 750 block will be a 750 twin, the 750 four started as a 1980 model.

If you are looking for a block to do an 810 on a 650, then you want a 1980 KZ750 block as it has provisions for the 650 roller cam chain.

Contact the guy you are getting the cams from, I'll bet he has one

You can download the manual at kz.mbsween.com/

Post edited by: steell, at: 2006/12/25 20:55

thanks !!!! im dumb!!! iv been looking for so many different parts for my project im geting years, models all mixed up!

thanks for making sure i get the right specs steell!

its a 3mm over bore from 66mm to 69mm for the 810 so even an out of spec 738cc(actual displacement of a 750 four) block would work, the bore job will take care of anything that hasnt gouged out/worn the cylinder wall more than 1.5mm in any spot. the block I had rusted cylinder bores, and after a bore (and hone) you would never know there was anything wrong with it.
happy holidays
Scott

Got lucky and found one a few weeks ago. Is in great shape and got a real good price on it. Thanks to you guys on pointing me to the correct year.

Have read this (get a 750 block) more than a few times over the years but no one pointed out or explained the differances in the later years cept for you guys.

One thing that surprised me is how thin the liners will be after boring but Wiesco and you guys have done it so many times I have no dought it being fine.

Cyl checked out at 2.593 plus or minus 1 or 2 and the bore calls for 2.717. Liners are approx 100 thous so they'll end up at just under .040 thick. Useless info sure but wanted to share it.