jetting for fmf??

[scooby61]

hi i just got into 2 strokes recently and have a problem with plug fouling. i don't foul them too often but i get some spooge and have a dead spot about mid throttle. i have the factory jetting chart but my bike has a fmf fatty and power core two pipe. do i need to go a step richer or leaner to compensate for the pipe or does it not make a difference? :bang:

 

[sick 96 250]

go to fmfracing.com and that will help you, look at the tech center then go to jetting

 

[scooby61]

thanks i'll try that

 

[Mike_socal]

Also keep in mind their jetting specs are with 50/50 mix of pump and race gas.

 

[gonzo843]

I put a Factory Fatty and shorty on my 125. I had to lean the pilot 3 sizes the needle 1 clip and the main was ok and I am riding in 40 degrees. You dont need to richen if your fouling plugs. You need to lean everything out. Go one size at a time till you get it right. FMF's jetting on their site is for stock bikes.

 

[sick 96 250]

There jetting always seemed to work for me on my bikes. I couldn;t get the jetting correct on my 96 rm250 with fmf pipe, rad valve and carbon fiber reeds, once I put there recommendations in it stopped smoking and kicked my butt a few times. I was using 93 pump gas also so in my book there pretty on point, may need to adjust a little but its somewhere to start

 

[gonzo843]

If you notice their jetting specs are just about what stock is. Most of the time they are the stock settings.

 

[sick 96 250]

Arent there jetting specs with there pipes on them, I think thats what it says...... Maybe not tho

 

[gonzo843]

It doesnt specifically say it's for their pipes. Also some of the pipes could require different jetting from others. Like it says they are starting points for jetting.