Oct 8, 2005
Hello all, I'm attempting to do my first top-end rebuild and have one question: How do you go about choosing the right size piston?? I looked at Wiseco's website under the Pro-Lite category and they have have 4 different sizes listed in increments of .50 mm from 54.00 up to 55.50. I briefly measured the cylinder with a micrometer (in inches) and it looks pretty close to the 54.00 measurement. The cylinder is stamped "A" to which I read somewheres this deals with piston size or something to that effect. Also would the piston be labeled as such too (I haven't disassembled it yet)? The piston and cylinder look in very good condition other than it looked to be running a little rich becasue of excessive carbon buildup on the piston dome. Any help would be greatly appreciated.

P.S. - I'm also going to be purchasing a new clutch kit, any thoughts or recommendations on which brand to go with?? Keep in mind I'm looking for the best value, not a lot of dough to throw around. Thanks!



Jan 9, 2005
A little carbon on the piston is fine...

If your running a castor based oil you will have more carbon then petroleum or synthetic based oils.

(A) cylinder uses an (A) piston, (B) uses (B) etc...

If your talking about the CR125 the stock Honda clutch is second to none. If you want more bite you can use three CR250 clutch springs and three of your CR125 springs every other spring location. This will increase your lever pull a little bit.

If your driven plates are aluminum you can use steel ones from a different year to increase longevity. This will be similar to adding a fly wheel weight. If it has aluminum plates and you switch to steel your oil will also stay much cleaner between changes and all that metal crap that comes out in the drain will be gone.
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