top end help

[drtydru]

I have an 04 ec250 that was converted to a 300 and I want to change the top end. I am new to gasgas and I see that there are a few options as far as what top end kit to get. Any info that would direct me to the correct kit to buy would be very helpful. Im just not sure how to tell what kit I need.

Thank you

 

[hannesd]

look at the rear of the outside of the cilinder to see what,stamp it says.
can be A,B,C or even D, this gives you an idea of what oversize piston was put in.
measuring the piston to cilinder sleeve is even better to get the right size of piston.
allso, look very closely at the sleeve for scratches and maybe cracks.

hannes.