FMF Fatty Jetting - scored some cheap pipes and need advice

[BlueMalibu]

Got super lucky and scored some FMF Fatty's and PowerCore 2's for $100 on Epay.

 

I have owned my Bansh since 1988 and it has had stock exhaust until now. It currently has no airbox snorkel (but has lid on) and a K&N filter with outer wrap. I ride at 600 to 1000 feet and usually 60-80 degrees. I have 220s in now with stock pilot. I have dialed this in over the years and it is right on around 65 degrees. I run 32:1 yamalube R.

 

So FMF recommends 260s with a 30 pilot - stock airbox no snorkel.

 

I looked through the long jetting poll and some people with similar configs look to be running up to 330! But others are running 270. That is a pretty big variance.

 

What do you all think. I was going to put in 270s to start.

[00sheerzr]

i would start at 300 and work your way down , you might need 27.5 pilots

[GrMeyer]

It depends on if you want to run the lid or not.

 

With the lid

Mains - 310

Needle - Middle

Pilot - 27.5

Air Screw - 1-1/2 Turns from fully seated

 

With the lid

Mains 270

Needle - Middle

Pilot - 27.5

Air Screw - 2 turns out from fully seated.

 

All this is a starting points. Each bike is different from one another. But those should get you close for starting.

 

Read up on this site as well if you havent already.

 

http://www.dfn.com/benkaren/jetfaq.html

[GrMeyer]

First one is for without the lid. Sorry I didnt catch it tell i hit send... And it doesnt have the edit button anymore.

[BlueMalibu]

Ok, thanks all.

 

I think I am going to go ahead and start with the 270s. I mostly trail ride and there is water and a lot of dust at times so I plan on keeping the airbox lid on. Plus I have some 270s. I also have some 260s but looks like I need to order up a few fatter jets as it looks like I will be going richer, if anything.

 

After I get them in and take it for a run I'll report back on how close they are.

[Midway USA]

Ok, thanks all.

 

I think I am going to go ahead and start with the 270s. I mostly trail ride and there is water and a lot of dust at times so I plan on keeping the airbox lid on. Plus I have some 270s. I also have some 260s but looks like I need to order up a few fatter jets as it looks like I will be going richer, if anything.

 

After I get them in and take it for a run I'll report back on how close they are.

 

I ride in Kansas and at LS OKLA. I have FMF Gnarly's w/Power Core II silencers. I end up with 290's in 40-60 degree weather w/lid, 280's in 70-90 degrees w/lid and usually pull the air box lid above 90's rather than rejet

[BlueMalibu]

OK, got my pipes on. I put the 270s in with the 130 pilots.

 

Boy, the pipes sure woke up my shee! Ran great, for sure the power comes on sooner and harder. Shoot, I have had the banshee for 22 years - should have put pipes on long ago.

 

Anyway, riding in the woods behind my house it seems fine. Was about 60 degrees. I don't think it is running rich for sure. Ran it at WOT on the road on the way back and it made a lot of power but didn't feel lean. However, I may bump up to the 280s just to be safe.