Fatty jetting Problems

[bansheeman350]

Whats going on guys? Im having jetting problems! I currently have fmf fatty pipes with spark arrestors,stock carbs,boyesen power reeds, an old school fmf powerlid,and a stock motor, and im at sea level for altitude. I have 290 mains,25 pilots,needle with clip in the 3rd spot from top, air screws set at 1.5 turns out. And basicaly my banshee runs like crap. So any advice on what my mains,pilots,clip settings,and air screws settings should be at please let me know. All advice is greatly appreciated.

[Banshee~]

Whats a fmf powerlid? What do you have done to the airbox? lid off, just holes drilled, snorkel removed, no airbox? And what is the temp.?

[bansheeman350]

Whats a fmf powerlid? What do you have done to the airbox? lid off, just holes drilled, snorkel removed, no airbox? And what is the temp.?

447201[/snapback]

 

 

A fmf powerlid is an older version of the new powerlids, the one I have is made of aluminum with 10 holes on the lid. I have no snorkel on my airbox. And the temp where I live now in cali is during the day its around 60-70 degrees and at night its mid 40's to 50 degrees.

[Hilarious]

What exactically is your bike doing. Is it runnin like shit at low rpms?

Not gettin in the powerband or what?

I have fatties, no air box lid, vforce3 reed cages & a K&N airflter.

340 mains, 27.5 pilots, needle in middle position and i think my air

screws are about 1.5 turns out.

Im in central MS tho @ bout 400 ft above sea level.

Is the choke crossover tube connected between your carbs?

[bansheeman350]

What exactically is your bike doing. Is it runnin like shit at low rpms?

Not gettin in the powerband or what? 

I have fatties, no air box lid, vforce3 reed cages & a K&N airflter.

340 mains, 27.5 pilots, needle in middle position  and i think my air

screws are about 1.5 turns out.

Im in central MS tho @ bout 400 ft above sea level.

Is the choke crossover tube connected between your carbs? 

447231[/snapback]

 

There is no mid-top power. Power seems to just coast, 1 and 2 gear are powerful but 3-6 gear just aren't. Any helpful hints

[Hilarious]

Have you checked you plugs? What do they look like?

You may be lean on your mains.

What kind of air filter do you have? Is it clean?

[Wallrat]

I'd try 330 mains and maybe even a 27.5 pilot. Where's your airscrew at? Those mains should be too rich so try working down from there. Oh and move your needle to the 4th position from the blunt end. For some weird reason, almost every FMF bike I've ever seen loves that damn 4th clip.

[Banchetta]

I'd run it wot in 6th gear and shut it down. Pull the plugs and see what they tell you. If they are black then go down to a 270 and try that. Are you still running a stock filter??? Make sure you didn't over oil it..Like wallrat said....every fmf piped shee I ever dialed in likes the 4th clip w/ aftermarket reeds and 5th clip w/ stock reeds...and yes, make sure the choke tube between the carbs is in place. (1/4" x 2" long)

[bansheeman350]

I'd run it wot in 6th gear and shut it down. Pull the plugs and see what they tell you. If they are black then go down to a 270 and try that. Are you still running a stock filter??? Make sure you didn't over oil it..Like wallrat said....every fmf piped shee I ever dialed in likes the 4th clip w/ aftermarket reeds and 5th clip w/ stock reeds...and yes, make sure the choke tube between the carbs is in place. (1/4" x 2" long)

447388[/snapback]

 

Man o Man jetting on this bike is . I'll move my clip down to the 4th clip from top. And about the mains I dunno if i read it here or on some other forum but correct me if im wrong I been told that 290-300 is with lid on and 300-340 with lid off. I currently have 25 pilots in my carbs and air screws set at 1.5 turns out from turned in. And everything else on my carbs are in place and nothing is loose. My bike has no power in mid-top power just seems to coast. I'll figure this problem out yet.

[Hilarious]

I been told that 290-300 is with lid on and 300-340 with lid off.

 

That sounds good. Thats how it was with my bike.

I have my needles set in the stock position because thats where my bike seems to run best at. There are lots of guys in here that are runnin fatties and they have their needles raised up a notch, 4th clip from the blunt end. Move your needles up a notch like Banchetta and Wallrat said and go from there.

[Banchetta]

Man o Man jetting on this bike is  .  I'll move my clip down to the 4th clip from top. And about the mains I dunno if i read it here or on some other forum but correct me if im wrong I been told that 290-300 is with lid on and 300-340 with lid off. I currently have 25 pilots in my carbs and air screws set at 1.5 turns out from turned in. And everything else on my carbs are in place and nothing is loose. My bike has no power in mid-top power just seems to coast. I'll figure this problem out yet. 

447829[/snapback]

Plug test......plug test. If you have a hard time reading the plugs then post a pic after a wot run in 6th gear...also....mid to top.........disconnect the parking brake switch by following the wires towards the gas tank until you find the connector. Disconnect. Next look above you left exhaust and you'll see a little black box w/ a 3-wire plug. Disconnect it..then make sure the choke tube is in place between the carbs 1/4" x 2" long.

[Justintoxicated]

With my Fattys no Sprak Arrestors K&N and no special lid I ran stock pilot and 320 main for year. Very near perfect jetting, I would guess with a littl more restrictions a 300 would be about right at sea level. Depending on how much restriction the lid and spark arrestor is. 200-310 would be my guess. I moved the clip on the needle down one position (raised the needle itself one clip) from the stock location.

 

I would only change it one clip if your going to go with a larger pilot but you can play with the needle all you want

 

When you say it just seems to coast running a slightly lean condition will allow the bike to rev but it won't have the power or rev as clean as bike that is spot on. My Guess is go up on the main and fix the needle.

 

Then again I dunno wtf a power lid is I jsut pulled mine off compleatly and put on an outerwear.

Edited December 17, 2005 by Justintoxicated