XR650L Smoking and Stumbling Off Idle


6 replies to this topic
  • druss6

Posted February 13, 2008 - 06:35 PM

#1

I just picked up a 2004 XR650L and have been running through the usual mods. I just got everything back together, but now it seems like it might be running a bit rich. It has a pretty pronounced stumble or stutter right off idle, and smokes a bit (blue smoke). I was hoping somebody had a similar setup and had some ideas. I'm running pretty close to sea level. Here is my setup so far:

White Brother E-series exhaust w/ 12 disks
Smog kit and snorkel both gone
Uni air filter
Slide drilled
Dynojet jet kit - 165 main jet, stock pilot jet, needle set at 3rd groove, fuel mixture screw out 2 turns

Any help would be appreciated.
Thanks

  • scalejockey

Posted February 13, 2008 - 06:54 PM

#2

blue smoke? Black or gray would be rich fuel. Blue would be more of worn rings. Put a new plug in and check the color of the old one.

  • druss6

Posted February 13, 2008 - 08:28 PM

#3

It just occurred to me that the smoking was oil and grease burning off the newly installed exhaust. I had to lube the hell out of it to get it on. In any event, I still need a solution to the off idle stumble. Thanks for the reply though.

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  • tgstoken

Posted February 13, 2008 - 10:03 PM

#4

Try turning the mixture screw in or out to simulate a richer or leaner conditon. I had a pretty bad stumble on my '93 650L, it turned out to actually be the main jet. I had a 165 in and it was too big. When I installed the 160 main, the stumble went away. I am running a Supertrapp racing series with 16 discs (loud), twin air foam filter, uncorked, de-smogged, Dave's mods, 160/60 jetting and stock engine. My bike runs perfectly and my elevation is around 500-1000ft.

  • Denn10

Posted February 13, 2008 - 10:24 PM

#5

Try turning the mixture screw in or out to simulate a richer or leaner conditon. I had a pretty bad stumble on my '93 650L, it turned out to actually be the main jet. I had a 165 in and it was too big. When I installed the 160 main, the stumble went away. I am running a Supertrapp racing series with 16 discs (loud), twin air foam filter, uncorked, de-smogged, Dave's mods, 160/60 jetting and stock engine. My bike runs perfectly and my elevation is around 500-1000ft.


165 DJ main jet is like 160 stock Keihin jet. I think your problem is in the stock pilot and air screw, you should be 55 pilot. Lean pilot will cause stumble off idle. I have that same exhaust and i think if you change that pilot and go 2 1/4 to 2 1/2 on the air screw like it says on daves mods you will notice a better response.

  • martinfan30

Posted February 14, 2008 - 09:45 AM

#6

Check all that has been posted already. How many miles? You may have bad oil control rings. Or if it smokes only on startup, valve guide seals leaking.

When I first put my Djet kit in my old CV carb, I first tried the 165. It did something similar to what you stated. I had to go with the 160. Ran great after that. Although I am at 4300 ft.

  • Motosprtman

Posted February 14, 2008 - 11:53 AM

#7

165 DJ main jet is like 160 stock Keihin jet. I think your problem is in the stock pilot and air screw, you should be 55 pilot. Lean pilot will cause stumble off idle. I have that same exhaust and i think if you change that pilot and go 2 1/4 to 2 1/2 on the air screw like it says on daves mods you will notice a better response.


Yup I agree. This be the problem with yer poor throttle response, the pilot needs to be changed and etc as above. :applause:





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