My bud has a 99 QR 250 4x4. We were doin some holes at Marienville. After we left his bike just up and quit after about 20 min. I looked at it and found that the plastic screen in front of the head was obstructed with weeds. I know the motor got hot. It will still turn over, but wont start. The nylon pull start rope even melted. Also he isnt getting spark. I think he may have fried the rings. How hot does it have to get to fry the rings. Hopefully it will fire when we get spark to it. I put my finger over the plug hole as he turned it over and it still blew past my finger. Guess he will have to do a compression test. Any idea what the psi should be?