piston rings

Alright lads, I'm new to the forum so cut me some slack! I have been riding for about a year now, and slowly working my way into the technical stuff, I've just bought myself a 2 stroke (Yamaha DT125re 2006), and I'm thinking of getting a new piston kit and replacing it. Can someone please...

I recently bought a 2000 XR200R. I never thought of this while buying it but when I was testing it, it was smoking like crazy (it's four stroke) and there was a lack of power for a 200cc engine. When I got home, I drove it to a trail and thats when it died. First, it wouldn't shift back into...