Replacing Pistons

[SinstaNSR]

How necessary is it to replace 2 stroke pistons on a top end rebuild especially if its never been done.. ?

[Motu]

Measure and report.....

[Racey Rider]

Not enough info in the question.

After 1000Km - why is the rebuild being done? If the piston looks alright, just change the rings.
After 10 000Km - Probably doesn't need it, unless obviously damaged. But if money is no problem, might as well change pistons too.
After 100 000km - Probably needs doing!

We went through this in a thread last week about two stroke reliability.
It depends what you expect from the motor.

[The_Dover]

shouldn't a hardcore speedfreak apprentice mechanic with 15 years riding experience know such gems?

what do you fix? lawnmowers?

[Forest]

How long is a piece of string?

[Jonny Rotten]

whats a piston ?

[Maha]

How long is a piece of string?

Its the distance between the two ends.....thought everyone knew that?....

[lukelin250]

why not may aswell save you doing it some other time

[Mr. Peanut]

Replace pistons every 60000km unless you see obvious signs of wear. Rings circlips etc... every 30000km. (Using a good oil, letting it warm up and not redlining every gear helps.)