piston replacement on a 400 1999

Soon expect renewed cylinder. It will be made in zero tolerance, thats 92.00.

Am in doubt as to use original or pro-x piston.

By manual, piston diameter should be between 91.945 - 91.60. Probably new yamaha piston varies in this tolerance.

In prox catalogue, there are 3 sizes, A, B, C, (91.92, 91.93, 91.94).

So the biggest pro-x oversize is still smaller than minimum service limit diameter given in manual.

If I check back, 1998 has smaller piston size service limit, that's 91.92-91.935.

I presume they are offering '98 model tolerance for all 400's.

Piston I took out, was running more than 3 years, closer to 5, was measured 91.95.

Those are the only brands, i can lay my hands on with decent rebate, so no other piston brand is an option.

Any thougts?

Contacting prox is as talking to wall.

Through dealer, managed to get answer from pro-x.

They have 91.95 in production, although not listed.

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