Piston trouble!

[superman]

I have a 85 200x, and today when riding it started running like it was out of gas when u would be in full throttle , so i took the plug out and it was covered in oil, ive been figuring it needed rings or piston because it has been smoking quite a bit , so does this sound like symptoms of rings or piston being shot, because now i cant even ride the bike it will start but u can only give it quarter throttle ,anymore than that and it dies

[whiteman350x]

Sounds like you at least need rings. When you pull the motor apart, take it to a shop and get them to measure the cylinder. They can tell you if it needs to be bored. If the cyl is in spec, measure the piston to see if it is out of round or worn. It piston measures good, then all you need is rings.

[samster143]

A compression check will give some info on the condition of the piston/rings/bore. About 150psi is normal. Less than 120 or so and she won't run too great.