Author Topic: Oversize Piston / Rings Guide  (Read 1853 times)

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Offline CG2000

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Oversize Piston / Rings Guide
« on: July 13, 2014, 08:42:56 PM »
Does anyone have link / info / reference for understanding when to do what in terms oversize pistons, oversize rings, honing etc? I'm sure this info will be on here somewhere but as usual I can't it (forums eh?).

Background: I have a 76 CB750F engine, with about 49,000 miles, looking to get it up and running pretty much stock, not interested in 800cc + overbore right now.

Cheers, C.

'76 CB750 | '72 CB350 | '96 XR650L | '06 KTM EXC 450 | '02 KDX220R

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Oversize Piston / Rings Guide
« Reply #1 on: July 14, 2014, 10:04:27 AM »
You're gonna be hosed if you don't go 836 (or bigger). No 1st, 2nd, 3rd, or 4th oversize available from Honda. I have not seen 810/811/812 kits available either. You can get the inexpensive 836 kits from CruizinImage ?? off EBay. You MIGHT find an oversize Honda set on EBay but that may take forever and it WILL cost you dearly.

If you want to stick to stock size pistons you'd best have a machine shop check your cylinders and pistons for tolerances. If appropriate then have them hone the cylinders and buy new rings. If your cylinders have too much wear for stock pistons you might try sourcing some used cylinders with low miles and have them checked and honed.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline lucky

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Re: Oversize Piston / Rings Guide
« Reply #2 on: July 14, 2014, 02:18:44 PM »
Does anyone have link / info / reference for understanding when to do what in terms oversize pistons, oversize rings, honing etc? I'm sure this info will be on here somewhere but as usual I can't it (forums eh?).

Background: I have a 76 CB750F engine, with about 49,000 miles, looking to get it up and running pretty much stock, not interested in 800cc + overbore right now.

Cheers, C.

Common practice is .020 thousands over the first rebuild if needed.
Then .040 thousandths over the second time.
Then .060 thousands the third time.

Offline CG2000

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Re: Oversize Piston / Rings Guide
« Reply #3 on: July 14, 2014, 11:27:26 PM »
Thanks everyone for your answers, very helpful! C.
'76 CB750 | '72 CB350 | '96 XR650L | '06 KTM EXC 450 | '02 KDX220R