FMF Gnarly Pipe

[Quadrider10]

Re: fmf fatty pipe

This is what the too y website has. So ima get 300, 310, and 320 jets. Sound good?


· Stock pilot jet, #32.5

· Stock Jet Needle #5J22, on the 3rd groove down from the top

· Needle Jet #345 P-6

· Pilot Air Screw ¾ turns out from full in

· Main Jet #310

 

[Quadrider10]

Re: fmf fatty pipe

I realy havent got to take a good look at my carb, where is the air screw and where is the jet needle?

 

[Larry's Shee]

Re: fmf fatty pipe

How cold is it in jersey right now? That will also affect your jetting. So what did you pay for it?

 

[Quadrider10]

Re: fmf fatty pipe

its about average is about 50, but i dont run really at all in winter.... only when it snows, nd thats has been once this whole winter. i got it for 50 +10 in shipping...

 

[blasty 95]

Re: fmf fatty pipe

60 bucks aint to bad least you got a aftermarket header its going to make a big improvement

 

[Quadrider10]

Re: fmf fatty pipe

but since i race mx, the temps will be varying between 60 and 80degrees F

 

[Quadrider10]

Re: fmf fatty pipe

yea. im also taking the airbox lid off too.

 

[Blaaster]

Re: fmf fatty pipe

I realy havent got to take a good look at my carb, where is the air screw and where is the jet needle?

Looking from the gear change side the air screw is mid bottom right, just above the float bowl.

The jet needle, is the needle with the grooves in it.

The needle jet is the tube the needle slides in.

Taking the lid off calls for at least one size up in main jet.

I just know I will get stomped on, but if you are going to punish the motor in the low/mid range riding MX, consider running an oil fuel ratio of 25:1.

If you do you, again you have to go up one more jet size on the main, and maybe lift the needle one notch.

The benefit of 25:1 is a little more compression and a little extra oil as you won't be WOT all the time.

Whenever you mess with jetting, be sure to do a plug chop.

 

[Quadrider10]

Re: fmf fatty pipe

ahhh ok thanks so is 300, 310, and 320 jets sound good? and also, if the plug chop is a tab bit lean or rich, and changing the jet would malke it over what it needs to be, i can just adjust the airscrew accordingly?

 

[Quadrider10]

Re: fmf fatty pipe

Looking from the gear change side the air screw is mid bottom right, just above the float bowl.

The jet needle, is the needle with the grooves in it.

The needle jet is the tube the needle slides in.

wait... the side with the choke?

 

[Larry's Shee]

Re: fmf fatty pipe

Air screw is 0-1/4 throttle opening. If anything ALWAYS run it on the rich side. As an engine goes from "perfect" to lean, power doesn't drop much, but exhaust tempuratures rise rapidly, leading to holes in piston. Even with 50* temps, start with 320 if that's what you get and try that. If it blubbers @WOT go one smaller. Take your jets and tools with you so you can do little tuning at ride spot. As the temps warm up then you re-tune by dropping jet size. Until you get confident in your tuning abilities rich won't hurt. As long as you aren't fouling plugs every 20 minutes it's not to rich. As I said earlier, ride it for about 20-30 min stop and look at plug. Be sure to clean around plug before you remove it, maybe wipe bottom of tank if lots of mud.

Look around on the site to find a sticky/pinned thread on carb tuning and read it. I:I

Air screw on choke side, kinda next to fuel inlet

 

[Quadrider10]

Re: fmf fatty pipe

thaks for the help!
ok so 300, 310, and 320 are good sizes to start with. mostly everyone in the sticky "jetting numbers" is running same setup as me and has no air box lid.i think ima use toomy's suggestions as a base line and mess around from there....

 

[Blaaster]

Re: fmf fatty pipe

Yup the air screw is on the choke side about level with the middle of the air input boot.

Air screw is used to adjust the idle, it will do little or nothing to the mix from the needle or main jet.

You need to firstly set up the idle, before you do plug chops.

The only way to correct lean/rich conditions on the main is to change the main.

 

[Quadrider10]

Re: fmf fatty pipe

ok i think i uderstand everything.this is my first time jetting, so thats y its like 20Q haha. and i see the screw now I:I im hoping i get my jets and everything by this weekend so i can jet and everything

 

[TechBlaster]

Re: fmf fatty pipe

Make sure when you receive the pipe you clean it good, then sand it down smooth, clean it again with denatured alcohol and paint it with high temp black header paint.
It will look good and last forever once done, good luck...

 

[dakine97]

Re: fmf fatty pipe

Id just clean it up

 

[blasty 95]

Re: fmf fatty pipe

Make sure theres nothing in it to

 

[brandoz28]

Re: fmf fatty pipe

I would paint it up. As rusty as it is it'll be pitted up a little bit.

High temp header paint ftmfw

 

[Quadrider10]

Re: fmf fatty pipe

Yea that's what I was planning on doing. How do I adjust the clip for the needle jet? Do u take out the 2 screws inside?

 

[Quadrider10]

Re: fmf fatty pipe

nvm i got it. when i get it, its gonna be cleanded a lot lol its gonna look nice. i just hope that it will fit the powercore 2 scilencer, and wont have to make something special to make it fit