hi im new to the form just have some ? i have a 2000 ttr250 that was runnung great and now nothing so i pulled the carb cleaned everything put new gas pulled plug and its the wrong plug guy before me stuffed a 12mm plug in it insted or the 10mm so im stuck no hely coll will fix that so i checked fire and have good fire i put plug back in couse im allready scewed and the bike blows air back out the carb and wont hit a lick sprayed starting fluid just to see if it would hit and nothing any help would be nice thinks for your time....
If its blowing air back out the carb I would guess something has happened to the intake valves and when the bikes doing the compression cycle ur intake valves are open. This could be becuase if incorrect timing or bent intake valve stems. My guess is uv had a cam chain slip. That would be the first thig I would check. I had a cam chain slip and it caused my piston to hit my exhaust valves. The cam chain had just reached the end of its life. After I got a new one I relise how stretched it was.
Anouther thing to check would be the teeth on the cams this can also cause a jump.
That's my suggestion anyway Good luck
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A dried up puddle is a missed opitunity ;)
Melbourne
Australia
plug in it insted or the 10mm so im stuck no hely coll will fix that so i checked fire and have good fire i put plug back in couse im allready scewed
and the bike blows air back out the carb and wont hit a lick sprayed starting fluid just to see if it would hit and nothing any help would be nice thinks for your time.... 
