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Posted

Hay guys,

have a ? about pipes.Just got some new pipes for christmas,fmf fatties.put them on and changed the main to 290,(all stock other than the pipes)just wasn't getting the pop shee had before.what should i do next,should i change the pilot,all the help the better. thanks

Posted
Hay guys,

have a ? about pipes.Just got some new pipes for christmas,fmf fatties.put them on and changed the main to 290,(all stock other than the pipes)just wasn't getting the pop shee had before.what should i do next,should i change the pilot,all the help the better. thanks

 

FMF's like a fatter pilot, and if you have stock carbs, put in a 27.5, and set both air mixture screws at 1.5 turns out. You may have to adjust the air mixture screw a few times, to get it right.

Posted
Yea if your running A stock air filter and A box lid with snorkle 290 mains are too fat.Start at 260 and do the plug chop.

 

I would take the airbox lid off, you'll notice the performance gains a lot more with the airbox lid off!! Then the jetting depends on your elevation, temp, fuel oil ratio, and type of gas your using!!! Oh by the way FMF web site for jetting sucks!!!! I have a 2004 yz250 and I put on a fmf factory fatty and titanium 2 silencer and the jetting specs they gave I was running way lean and I was in the same situation that they describe! If you need anything else just post and everyone will help you out the best we can!!!

Posted

i put in the 270mains and took the airbox cover off,shee ran real well.and i'm at sea level,30 to 50 degres

but i want to keep the airbox cover on.alot of water here.thanks for all the help

Posted

Get rid of the snorkel and try it where you have it now. You should have to lean it a little more to get it right on. But do a plug chop so you can be sure. I am willing to bet you are a hair lean w/lid off and 270's, so be careful. When you said it ran like shit w/the 290's, was that w/the lid on?

Posted

260s with 25 pilots hsould be dead on if your running an air box with lid, and have no other mods. That's the setup I have run for a long long time now, and have had 0 problems.

 

You really have to let us know what temp and altitude your running at too. I bump up to 270s when the weather drops below 40

Posted
260s with 25 pilots hsould be dead on if your running an air box with lid, and have no other mods. That's the setup I have run for a long long time now, and have had 0 problems.

 

You really have to let us know what temp and altitude your running at too. I bump up to 270s when the weather drops below 40

Posted

Actually, I can't take credit for that idea, a member here sent me the pics to host for him, but I can't remember who it was. I have a pro-flo adapter, but if I had to do it again, that would be how I would do it.

 

Hope you got your jetting right for those FMFs!

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