I bought a used atv honda 2004 trx450r and it idles rough and the exhaust gets red hot. I took apart carb and cleaned with carb cleaner but still runs rough, it has 87 octane gas in it as well. There is a black know which i think is for idle and when i turn it the idle changes but is still rough and when i hit throttle it backfires and u can even see flame out exhaust, any help guys?

 

It is running lean. Did you pull the pilot and verify it was free of debris? If so you should go up a size or 2 and see if that helps. Also, you need to use premium in these. 91 octane as they have to much compression to run 87 reliably.

 

What do you mean pilot, I am new to this so may need a bit more direction. I assume you mean the jets go up a size or two? I can put the higher octane in and see if that helps as well.

 

The higher octane won't cure your issue, but is necessary. You could also have an exhaust or head gasket leak potentially. The pilot is a jet, accessed through the float bowl. It is responsible for fuel delivery up to approximately 1/4 throttle. The opening is small and one of the first places to gum up and clog on a machine that has sat with fuel in it.