Strach

Member
Nov 22, 2000
38
0
I have TTR250 with a Biggun system on it. I noticed that sometimes it seem to idle high. When I burp the throttle it comes down to the proper rpm. I have tried to adjust the pilot screw and still no change. I pulled out the choke once while it was reving high (hot) and it even revved higher
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I'm running a 146 main jet and moved the needle one position richer. The high idle can be felt even while I'm riding sometimes. Any ideas what could be causing it?

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Strach

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Boit

Sponsoring Member
Sep 5, 2000
116
0
I've experienced the same exact problem with my '94 KLX250. It had been running great for months and started this high idle problem suddenly. As far as I can tell, the culprit seems to be a worn carb slide bore wihich causes the slide to sometimes not bottom completely when the throttle is closed. It has the aftermarket Mikuni 33mm pumper carb and this seems to be a common problem. I won't know until I send the carb to Kientech for a plating of the bore. I really don't want to spring for a new carb if there is some other problem. I've already cleaned the carb jets and circuits completely, and made sure I had no air leaks when I reinstalled it. A lean condition could cause a high idle. This may turn out to be a difficult problem to solve, although I ran into this problem with my '00 YZ426 and it was due to an air leak where the air filter boot mated to the carb. Once I corrected this leak, all my carburetion problems vanished.
 

Strach

Member
Nov 22, 2000
38
0
Hi Boit!
Thanks for responding to my question. did your similar problem get worse over time with your YZ and was it intermitant? I noticed mine stated to do it mildly and got worse over time. Would a lean problem do that? weather has been consistant. I'm thinking (I'm hoping!)it could be in the same fix as your 426. Do you see any similar signs in my case?
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Strach

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