Jetting For Fmf Fattys

[yellabanshee]

hey there.....i am new to the 2 stroke thang........but i got a 2003 banshee

with fmf fattys and powercore 2 pipes......and K&N filter w/air box lid off.....

 

i road last weekend and noticed a dead spot in the throttle.......

i was going about 30mph med. throttle and when i hit the gas it boged for a second.........then the powerband kicked in fine..........i also have bogging in

6th gear..........and the bike is at stock pilot 25 and 280 mains.......

 

any thoughts? help please

 

thanks

[BenBB]

Just from the jet sizes you listed, I think you should try going richer on both the pilots and the mains, but every Banshee is a little different so you might possibly be rich on one of the circuits...

 

An easy way to see if you're rich or lean is to use the choke; when the bike is fully warmed up, ride it and pop the choke out to the first notch. If the bog gets worse in a certain throttle range, you know it's rich...if it gets better you know it's lean.

 

Now, the mains are responsible for mixture from about 3/4 throttle to WOT. The pilots control mixture from idle to about 1/8 throttle, fine tuned by the airscrews. The needle clip position fine tunes the mixture from about 1/4 to 3/4 throttle. What I usually do is dial in the mains first, then the pilots/airscrews, then adjust the needle clip position if necessary.

 

For your mods, I would start with 30 pilots, airscrews 1.5 turns out, needles in the stock middle (3rd) clip position, and 320 mains. Should be a safely rich place to start, if it bogs at WOT drop a size on the mains until it revs out clean, and adjust the airscrews in (richer) or out (leaner) for a clean idle and off-idle response.

 

Got some more stuff about jetting in the FAQ in my sig if you want to check it out, it's hard to tell from your description but I would try going richer and see if it gets better or worse, and go from there. Good luck.

[bronco91shee]

mine felt the same way, i went to 30 piolts. it seems to fix it. Im runnin 280 manis i think. if not that, maby try ur jet needle clip. peac out

[yellabanshee]

Hey BenBB...........i tried the FMF jetiing giude at about what you said

 

30 pilots and 300 mains...........it would not even start with new plugs...

 

i put the 25 pilot back in and the 280's and i fired up and runs good

excpet i think it still needs some thing else because of the

boggings in mid area...........i just pulled the plug after a long ride and

they were a little wet and black..........so i think i will try 270's

what do you think?

i think maybe also trying a 2 turns out instead of 1 1/2

 

?thoughts?