life after .060 over bore

so im bike shopping; its a 75 mk3, with 28k mi. and new pistons, rings

how much life to expect after the cyl have had a .060' overbore?

850dunstall said:

so im bike shopping; its a 75 mk3, with 28k mi. and new pistons, rings

how much life to expect after the cyl have had a .060' overbore?

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If it's an 850 it should last as long as a fresh standard bore.
If it's a 750 keep an eye out for cracks appearing behind the outer base nuts. If you don't get cracks it will last a long time. Jim

Wonder why it was bored out so much for so little life as 28k is not much milage.

Ashley

ashman said:

Wonder why it was bored out so much for so little life as 28k is not much milage.

Ashley

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Broken circlip let wrist pin put deep groove in cylinder? Broken valve head put big gouge in cylinder? Piston seized really big time? Or maybe it just needed .010" over, and the PO decided he'd like the extra displacement. I've known several owners who decided to go with the .060" over pistons just for the extra 33 cc displacement. Most of them also went for aftermarket pistons and more CR at the same time. Hard to tell why Norton owners decide to do things. They're an odd bunch :lol:

Ken