yz250f help

[Grensjos]

i have a 2004 yz250f. I am looking for some advice. i ran the bike all last year and it never gave me any problems. I put the bike away for the winter and started it up a few weeks ago and it still ran just fine. After i ran it a few times i noticed that i was starting to get some back fire on decel. I checked valve clearance and intake is .001" over spec, and exhaust is right at the lower spec limit. I am wondering if i maybe sucked something into the carb?

any advice would be great

thanks
grensjos

 

[oldguy]

Backfire on decel is often due to lean on the pilot circuit. Were you running last week when it in the 70s or was it colder out? On my sons bikes we use the zip tye fuel screw to make minor adjustments.
Also make sure your airfilter is clean and not over oiled. You also could have some dirt or varnish plugging up the pilot jet. A good thorough carb cleaning might help

 

[Grensjos]

thanks for the reply, i think that i may have solved the problem. The gas that i filled the tank with last was about 6 months old and had broken down and must not have enough octane. Stupid mistake on my part!

thanks
grensjos