put the 138# jet back in the 350x..........

[Ddw350]

awhile ago i posted some main jet questions on my 350x,after alot of input i went with a 140 main due to my mods[supertrapp,k/n filter] at first it seemed the same,then i started to notice the tip of the exhaust was blacker than usual,plug looked the same as always,but it seemed alot harder to start,i know the main jet doesnt have anything to do with starting[i think] but this seemed strange.also backfired more even after adjusting the air screw.so i put the 138 back in last week,set the air screw back to roughly where it was now it starts on the 2nd kick every time,and the exhaust isnt AS bad but still black...also do i need to turn the air adjustment screw in or out to limit backfiring during decelleration?

[Dirtcrasher]

awhile ago i posted some main jet questions on my 350x,after alot of input i went with a 140 main due to my mods[supertrapp,k/n filter] at first it seemed the same,then i started to notice the tip of the exhaust was blacker than usual,plug looked the same as always,but it seemed alot harder to start,i know the main jet doesnt have anything to do with starting[i think] but this seemed strange.also backfired more even after adjusting the air screw.so i put the 138 back in last week,set the air screw back to roughly where it was now it starts on the 2nd kick every time,and the exhaust isnt AS bad but still black...also do i need to turn the air adjustment screw in or out to limit backfiring during decelleration?


I can share a similar experience. My stock SX had a 130 main - I added a Cobra pipe and got way too lean - I put in a 138 350X main and it was fine but backfired like crazy. All I did was back out my air screw about a 1/2 turn and the backfiring stopped and the 138 was a great match to the Cobra pipe with the airbox lid off.

[sittinguy]

Put some tools in your pocket and go for a ride.. run it up to 75% or so and shut it off quick, pull over and remove the plug and check the color, you should have a nice brown color, if it is white or light gray , it is to lean and could damage your rings,

[Ddw350]

mines usually blackish,its always seemed to be a little rich from the get go,even after i put the add ons on,im gonna try the 1/2 turn out on the air screw and see if the backfiring stops..........