[300ex] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

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300ex
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Posted by: sneekypete

I bought a 300ex that has been in a garage and hasn't been ran in a while I can get it started but it backfires and pops a good bit and I can't get it to idle without it killing. What do I need to do to get it back in good running shape?

Posted by: SET THE STAGE

the jets in your carburetor are probably clogged causing it to run lean. have someone who knows a decent bit about carburetors (unless you know how) check it out and clean what they can

things to also check
-take off the rear fenders and make sure the filter and air boots are tight and have no leaks
-make sure the header of the exhaust is tight up against the cylinder
-get a fresh spark plug dr8es-l or dr8es (runs a little cooler. meant for 300's with mods)
-make sure the gas is good in it

yeah. that's about it.

Posted by: sneekypete

well i cleaned the carb even though it looked clean already i emptied the gas and put fresh gas. I changed the spark plug and still doesn't idle and pops a good bit I have no idea what else to try. and suggestions?

Posted by: the Z Man

The popping could be an exhaust leak, Check the carb boot for cracks, air filter, valves tight, turn up idle a little bit.

Posted by: sneekypete

i got to the valves how do i check to see if they are tight?