when to change piston

[geoffro]

I have just acquired my friends 2005 kdx 200. I think I read somewhere of the standard pistons breaking...?
This bike, although now 7 years old was only ridden once a month and some months just stood. I have no idea on hours of motor, but it runs well, starts first time almost every time...you know...kdx reliability.
Should I go ahead and change top end?

 

[cornishwrecker220]

the 220 had a weak piston fitted as standard which resulted in them breaking, some broke with low hours on them (mine looked like new when i replaced it some 5000 miles later! ) your 200 piston should be fine however a top end rebuild is reasonably cheap & doesnt take long to do..like the old saying goes `if it aint broke...`

 

[EYY]

If you don't know if it's been done, rebuild the top end and clean the powervalves too. It's cheap insurance

 

[Joburble]

Give it a compression test. It will give you an indication of the top end without pulling it apart. Also take out the reed block and have a look inside at the piston and bore for significant signs of wear. Remove the exhaust and have a look up the port and do the same. If your compression is within specs and there are no signs of significant wear then you are good to go for maybe the price of a reed block gasket.

 

[reepicheep]

I bought a beat to death KDX200 and when I pulled it apart the piston skirt was cracked. So while the 220 is the real problem, the 200 piston won't last forever either.

Its been over 10 years, I'd say spend the $100 for a wiseco and be done with it.