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Please help identify this noise.

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So my 2002 YZ 125 is making this noise when I let off the throttle. Someone told me it meant the bike is lean so I put in a 430 main (stock is 420). In the video, I am running 40:1 with blendzal castor. However it kept making that sound. So I did a leak down test and there aren't any leaks. Then I switched to yamalube at 32:1 and it still makes that noise. In the video, you can hear how i set the airscrew super rich when I'm exiting the corner to compensate, but it still made the sound. The plug has stayed tan through all these changes. Anyway, any suggestions? Am I actually lean? Oh and my last top end was three rides ago (2 of them singletrack/tight woods). Thanks for any responses!

Link: http://s606.photobucket.com/albums/tt143/bootsandrew/?action=view&current=Produce_0.mp4

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It does sound a little lean off throttle or the idles turned up.

Changing the main wont help at that throttle postion, check your pilot size for your area and temperture and make sure the pilot circuit is clear.

Going from 40:1 to 32:1 actually makes the bike leaner," i know it seems wrong".

If you turn the idle screw out so it wont idle, does it still do it?

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Ok. I will give the idle thing a try. Also I knew that being more premix would make it run leaner, however I though that the bike was lean as in not enough premix.

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Fixed it! Turns out the carb was tilted too much causing a bad seal with the carb joint creating a small air leak. Bike is running awesome now with more power and it sounds much better. Thanks for all the help!

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