More jetting problems - I think

[Ghuds]

I posted a few months ago about problems with jetting and temp changes. The sled runs great in the morning at various altitudes (8000 - 10000') but loses top end and has a rough idle in the afternoon. The few times I rode it there was about a 20 degree temp change from morning to afternoon. I thought this was the problem so I dropped the main jet from 350 to 340 and dropped the needle 1 notch. Last Friday rode it and it did it again, but there wasn't a drastic temp change. The A/C recommendation for the alt. and temp is a 320 main but I have an SLP intake, V Force 3 reeds and an aftermarket can. Is there something else I should check or do you think I should drop the mains to 330's and try again? I dont want to lean it out too much and risk a burn down. By the way, the plugs look good (clean tan color) but they are wet when it starts running crappy. I tried to check piston wash on the mountain but couldn't see the piston top very well.

 

[diggerdown]

I take it by the jetting that you have a 900. I run my fuel screws out 1 & 5/8 turn, book says 1 & 1/2 but my low midrange is a little too hot there. I also run my needles in the middle, again due too mid-range heat. 320 jets at that elevation and temps over 20* I added air intake and speedwerx pipe. I think I could go down to 310's when the temp gets around 30* I have notice that if I have fuel with 10% ethanol it does not run as well especially with a hot engine. Friend of mine has a xp and has noticed the same thing.

 

[Ghuds]

Thanks for the advice - I think I'll go to 320's and raise the needle a notch and see what happens. It's been a unusually warm winter this year and the temps have varied a lot.