Fmf Fatty Jetting Specs

[tacoking]

I am running fmf fattys with a uni filter closed box with snorkel removed and 21cc Noss domes. fmf says to run a 260main and 30pilot. does this sound right? Seems like it might be to rich with the pilot. I am also at around sea level in 60-70 degree weather.

[northshore03]

i have fmf pipes, k&n and the lid removed, i run 300 mains and 30 pilots with the needle at the bottom clip. seems to work for me, there is no bog, plenty of power at the top. but that with the lid removed, i dont really know how much of a difference it makes when the lid is on or off.

[J..J.]

Fatty's, K&N, lid on, no snorkle, sealevel to 2500ft.

320Mains, 30pilots.

If she starts ok, and there is no hesitation when you blip the throttle 0-1/4, then I would leave the pilots as they are.

I would go up some on the mains though...

[2004LEBanshee]

will changeing the mains cause the bike to be harder to start or the blip of the throttle. Or is putting the pipes on going to change the way it starts and once you dial in the pilots thats it you dont have to do it any more.

 

Sorry not to steal your post.

[Banchetta]

270-280 mains w/ lid on, 290-300 w/ lid off, raise the needles 1 notch w/ aftermarket reeds or raise them all the way w/ stock reeds. STock pilots.

[Justintoxicated]

I was running sea level, glamis, K&N filter, no lid Fattys 320 main stock pilots (should have run 30 pilots though). Ran great, tid bit rich, but it would run slightly lean at night.

 

Does FMF list foam and stock foam seperately? if not, you might want to go a little richer. Also if they don;t list the snorkle mod that will make a difference, maybe you could mod the lid a little to let it breate more, or get one of the K&N lid tops.

[tacoking]

on fmf's web site they said with snorkel off but not mentioning type of filter to run the 260 30 setup. The uni doesn't breath to much better than a stock filter but I know a k&n would. I ride in dusty conditions so the k&n wouldn't be a great choice. fmf also listed 280-300main with the lid off. I guess Ill try the setup I got this weekend and see how she runs. I am running 100LL so if I am a little lean the higher octane should reduce my chances of detonating.

[Ducman]

I think this will help you alot. I have the FMF Gnarleys which actually came with Fatty jetting instructions, and I have installed a twin air foam filter with foam outerwear which has pretty much the same flow as stock. I tooks FMF's advice on the jetting and shee runs great. #30 pilots, air screws 2.5 turns out, air box lid on (snorkle removed), needles in the stock position (clip in 3rd slot from either end - middle position), #260 mains.

 

Compared to the stock pipes and jetting it seems to smoke slightly more on startup and doesn't idle up as high with the choke after starting and warming it up, but starts first kick when cold with the choke on the 2nd setting (all the way out). I tired the needle one position richer, not much difference. It seems to go into the band a little easier for the first couple of times after warm up with the needle in the stock position. I ride between 350' - 500' elevation. I run the Yamalube R at 32:1 if that makes any difference. It runs good with the #260 mains from 60 degrees up to 80 or so and goes into the band in the blink of an eye. Probably gets a little lean at 50 degrees but doesn't exhibit any signs of lean and looks ok on the plugs from my experience.

[tacoking]

cool, I hope to have good results this weekend at glamis.