Noob jetting question.

[Wertzy]

Ok so I picked up a set of FMF Gnarly pipes and was wondering how I should go about jetting for them. My engine is completely stock with a K&N with the lid on. Suggestions?

[kojack]

Ok so I picked up a set of FMF Gnarly pipes and was wondering how I should go about jetting for them. My engine is completely stock with a K&N with the lid on. Suggestions?

 

 

call fmf and see what they recommend. Take it from there as a starting point then fine tune it.

[dajogejr]

You riding temps and elevation help....

[Wertzy]

Well I'd say between 1000-1200 ft above sea level. As for temperatures...right now between 20-40* F. :yelrotflmao: Fuckin cold.

[dajogejr]

remove the snorkel if you haven't already.

250 to 270 main to start, might be a bit rich.

stock needle.

Air screws about 1.0 to 1.5 turns out, roughly....

You MIGHT have to up your pilots one, if it runs best with the air screw less than 1 turn out.

FMFs tend to like a fatter pilot, but...you're 1000 feet up and have the lid on.

 

Trying to start you off a bit rich cause it's cold (cold here in MI too...)

[fastrthnu]

remove the snorkel if you haven't already.

250 to 270 main to start, might be a bit rich.

stock needle.

Air screws about 1.0 to 1.5 turns out, roughly....

You MIGHT have to up your pilots one, if it runs best with the air screw less than 1 turn out.

FMFs tend to like a fatter pilot, but...you're 1000 feet up and have the lid on.

 

Trying to start you off a bit rich cause it's cold (cold here in MI too...)

 

 

fmf sez something like 260 mains 27.5 pilot stock needled clip on 3rd 1.5 turns out lid off for ballpark. but that was for your alt at 70 degrees.

[Wertzy]

remove the snorkel if you haven't already.

250 to 270 main to start, might be a bit rich.

stock needle.

Air screws about 1.0 to 1.5 turns out, roughly....

You MIGHT have to up your pilots one, if it runs best with the air screw less than 1 turn out.

FMFs tend to like a fatter pilot, but...you're 1000 feet up and have the lid on.

 

Trying to start you off a bit rich cause it's cold (cold here in MI too...)

 

Well I have two 280 mains right now. Should I try those? I'll have to pick up some 270's and 250's sometime.

[fastrthnu]

Well I have two 280 mains right now. Should I try those? I'll have to pick up some 270's and 250's sometime.

 

being that cold a 270 -280 might be you. colder air is more dense,. so more oxygen molecules will be packed in a particu;ar displacement, so you`d probley be lean at 260. need more fuel to make up for the denser air.

some 250-280 `s might get ya all year round. only about $2.50 a pop. but then again if your running with a lid 260 might be you. JBut yea,. try to 280`s you already have. better to run a lil rich than lean. ust gotta test n tune.

Edited February 1, 2007 by fastrthnu

[Wertzy]

Yeah there is no way I'm taking the lid off my airbox. I ride in too much mud and water to risk that. Hell, I'm even afraid to take off the snorkel. :yelrotflmao:

[fastrthnu]

Yeah there is no way I'm taking the lid off my airbox. I ride in too much mud and water to risk that. Hell, I'm even afraid to take off the snorkel. :yelrotflmao:

 

 

then you might want to begin with 260. still get some 250-270 though just to have.

[Wertzy]

Alright cool. I ordered from 250-320's. I think I have a wide enough range now of jets. :yelrotflmao:

 

Thanks for the help guys.

[Banchetta]

Keeping the lid on is pointless for pipes. Your down about 4hp w/ the lid on...Cut the last 1.5" off the end of the lid right behind the clips so you still have all 4 clips. You can use a skill saw, takes 2 seconds. This will allow all the air the motor needs and will keep the mud off the filter. You'll notice a huge difference w/ throttle response w/o the lid or modded lid. You'll then need at least 280 mains for those temps and some 260-270's for 70-90 degrees out. 27.5 pilots and try raising the needle to the 4th clip after you've done everything else. Let me know how you make out.