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2001 YZ250 Idle Issues

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I recently picked up a 2001 yz250 with a Pro Circuit Platinum pipe and Boysen rad reeds (i think, see picture below.)  The bike had been sitting inside for 2 years in an impound lot so I don't know the history of the bike.  The jetting is 165 on the main, 48 pilot, 2nd clip, air screw all the way in and the idle screw is up almost all the way.  The bike will idle hands off like this but it isn't really idling, its essentially like rolling on a little throttle. Once you open it up above 1/8th throttle, response is very good and the bike has a lot of power.  I figured it was a pilot jet/circuit problem and have thoroughly cleaned the carburetor several times so this is not the issue.  It sounds like the bike isn't getting any fuel/air until the throttle is cracked.  I'm wondering if the problem is in the reed valve, which is in good condition and was cleaned.  Could the design differences between the stock reeds and the Boysen rad reed cause this problem?  Could the reeds be too stiff and not letting enough fuel/air in?  Pro Circuit recommends a 175 main, 45 pilot, 2nd clip, and 1 turn out, I didn't think the jetting difference would cause this but I ordered the recommended jets anyway.  The spark plug is correct, clean, and gaped right   Any help is appreciated, thanks.

 

 

WP_20130922_004.jpg

Edited by Burgershark

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I recently picked up a 2001 yz250 with a Pro Circuit Platinum pipe and Boysen rad reeds (i think, see picture below.)  The bike had been sitting inside for 2 years in an impound lot so I don't know the history of the bike.  The jetting is 165 on the main, 48 pilot, 2nd clip, air screw all the way in and the idle screw is up almost all the way.  The bike will idle hands off like this but it isn't really idling, its essentially like rolling on a little throttle. Once you open it up above 1/8th throttle, response is very good and the bike has a lot of power.  I figured it was a pilot jet/circuit problem and have thoroughly cleaned the carburetor several times so this is not the issue.  It sounds like the bike isn't getting any fuel/air until the throttle is cracked.  I'm wondering if the problem is in the reed valve, which is in good condition and was cleaned.  Could the design differences between the stock reeds and the Boysen rad reed cause this problem?  Could the reeds be too stiff and not letting enough fuel/air in?  Pro Circuit recommends a 175 main, 45 pilot, 2nd clip, and 1 turn out, I didn't think the jetting difference would cause this but I ordered the recommended jets anyway.  The spark plug is correct, clean, and gaped right   Any help is appreciated, thanks.

 

 

attachicon.gifWP_20130922_004.jpg

Is your throttle adjustment unscrewed a little bit? this could cause an issue like that. Happened to me with the same bike

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The throttle adjustment was fine, I re-jetted according to what Pro Circuit recommends for that pipe and the issues went away.  After taking it for a couple rides and burning out the gunk it runs cherry now.

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