Which Colour/Letter Piston for My 125?

bronwynrayne wrote:

Can I safely run any one of the four pistons offered for my '06 YZ 125?
Surprisingly the ink indicator has worn off...

Do you mean A,B,C sizes?

bronwynrayne wrote:

Can I safely run any one of the four pistons offered for my '06 YZ 125?
Surprisingly the ink indicator has worn off...

Hondas4Life3 wrote:

Do you mean A,B,C sizes?

A, B, C, and D to be exact! There are four options within a very small tolerance, and I am wondering if there is a specific indicator for it other than the ink stamp.

If nobody has a better answer I will take an inside micrometer to it and get the tol myself, I just figured I would ask first as the helpful members on here have pulled through for me in the past.

The stamp only says what was installed when it was new. For the right piston size you will need to measure your cylinder.

Yes you could probably slap whatever piston you like in there but it's not optimal at all.

HenryA wrote:

The stamp only says what was installed when it was new. For the right piston size you will need to measure your cylinder.

Yes you could probably slap whatever piston you like in there but it's not optimal at all.

Thank you.

I will just have to do it the right way. I was trying to minimize down time while ordering parts.

Does the Manuel give the spacific cylinder spec for each letter?

Piston does not have a stamping on it?

Chances are, if the bike has a lot of time on the original plating, you will end up using the C piston, or possibly D.

My general rule was use an A for first initial build then a B piston for second and even third changes. C piston if plating is starting to glass over. But measuring it is the right way.