Big Bore??

archie2133

New Member
Hi guys,

Im wondering if you can help me. Im doing a top engine rebuild on my 1975 Honda Cb750f and I'm changing my piston rings.

Upon pulling the pistons out I found that the bore measures 65mm and the pistons are stamped "STD" for what I assume is standard.

When consulting my work shop manual it states that the bore and rings should measure 61mm.

Im guessing these pistons aren't from the original engine abd that the head has been bored??

Should I just leave the pistons and buy 65mm rings to suit??

Thanks

Archie


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irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
65mm is an 836cc bore. That's a great deal. Keep it and get your 65mm rings, as long as your sleeves and such check out okay.
 

cxman

Active Member
run a 180 0r 240 ball hone through the bores to deglaze if the bores are good and fit new rings
 

archie2133

New Member
Thanks guys. I've got it honed and ready to go. Will I aso need a different type of head gasket if it has been bored??

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irk miller

You've been mostly-dead all day.
DTT BOTM WINNER
Just a head gasket made for that bore. It can be the same material as stock, MLS, or copper.
 
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