Motorcycle Repair: kd 80, clymer manual, plug hole

Question
My son has a 86 kd80. It started loosing power when it warmed up. Eventually it just stopped running, is this a valve problem or a ring problem. Plug is firing and I cleaned the carb jets etc. It will start for 2-3 seconds and thats it...will not start again unless it sits for a while.

Answer
Ok, we need 2 do a compression test.  I would also suggest that u purchase a "Haynes" or "Clymer" manual for the machine as it will have all the specs u r gonna need for this issue.  If the bike shows a low compression, put about a 1/2 ounce of oil in the spark plug hole and repeat test.  If compression goes up it's the rings.  www.myspace.com/fullpower06