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77
Joined
11/30/2018
Location
Summerville, SC
US
scraprecon
11/30/2018 5:06pm
11/30/2018 5:06pm
Edited Date/Time
3/23/2019 6:38pm
Bike is a 2002 YZ250 2 stroke. It's acting lean on the pilot circuit. Hanging revs and popping on decel. Fresh top end, carb rebuilt. Float height set correctly. Reeds look good. New spark plug. Starts right up, runs great but sounds lean on the pilot. Stock carb pilot jet for the bike is 50. Went to a 55 and the air screw all the way in and it's still a touch lean, very light decel pop. Runs good though, no bog. If I turn the air screw out 1 turn with the 55, it starts to rise idle, hang, like I'm running out of fuel. I'm at sea level and around 65 degrees. 32:1 ratio with 93 pump gas. Seems weird that I have to run a 55 while others are running 45-48 and I'm still lean with the air screw all the way in. With the bike warmed up and idling, if I turn choke on it sounds good(little loaded up), revs nicely, no hang or popping. Sounds like a textbook air leak but my air leak resulted in a loss of 1 PSI in 6 minutes, which I think isn't too bad. Anyone have any ideas? I could go richer on the pilot(58,60) but I feel like I'm just masking the problem.
The Shop
Pit Row
Make sure you take the petcock off the tank and clean the screen and blow it out too. And make sure the cap is venting well. Test run the bike with the cap off to check.
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