help with some jetting issues

[runflat]

hey guys, havin a little bit of problems tuning my shee, just put a set of .020 over aggressive dune port cylinders on my shee, heres the details on the motor

 

.020 overbore aggressive dune port

stock stroke

stock head

stock carbs with 250 mains, 25 pilots, needles on the 2nd from the bottom clip

stock airbox w/ k&n filter

running 159-161 compression

91-110 50/50 mix at 32:1

elevation is 1055 ft asl

 

i started off with a 280 main and it was running super fat, so i dropped it down to a 250 but i cant really tell if its running fat or lean...it wont idle at all, you let off the gas and it falls flat on its face, i havent tried running brand new plugs in to tell weather or not the 250 is fat or lean but i will tonight...but im more concerned with the 1/4 to half throttle response because it spits and sputters untill you really crank on it then it clears up and runs like a scolded ape on the top end....any ideas would be greatly appreciated because im running out of ideas

[12 0 Clock P I M P]

adjust ur air screws and move your clip up

 

I would suggest working down one jet size......280- 250 is a big jump...try a 270......and a 260 first....then a 250 if ur still off..but work slow or u will lean it out.

 

with pipes try a 27.5 pilot

[06specialedition]

That needle seems pretty fat....On stock carbs with a ported 350 I like either the middle clip or second down from the blunt end. Try that with a 260 main and see where its at

[sleeper06]

Who did the aggressive porting?Is the lid on the box.To me a ported bike should need more fuel than that,340,27.5,needle in middle to start,carbs need to be synced up and opening correctly

[runflat]

ok so....i went to my dads tonight and picked up some more 110, dropped the clips on my needles to the 2nd from the top....turned my airscrews in all the way then back them out a half turn, started it up and it ran ok for a minute then started popping on both cylinders so i shut it down and turned out my airscrews to 1.5 turns out...fired it back up and it popped with ever crack of the throttle...shut it back down, pulled the needles and put them on the 3rd groove from the top, left my airscrews the same, and fired it up....still popping but now its fouling plugs....i dunno what im gonna do with this thing, i thought it was running lean but after today im pretty sure its still rich.... here is a pic of what the plugs looked like with about 3 heat cycles and 2 fouling out's...

 

[TNTS355]

These are my old jugs. When I was running these jugs I was around 320 mains and at 800ft, with stock 25 pilots. I dont remember what the needle was set at.

 

I used PC and T5 pipes.

 

One side looks good the other looks fat.

[runflat]

ok, bike is fixed, was a stupid problem, took it to jeff at f.a.s.t and he had it running in less then 20 minutes, that guy knows his shit.....the problem was my tors was working....my throttle cable was to tight so my slides were lifted ever so slightly and my tors was trying to kill the engine....i felt like an idiot when he unplugged my tors and loosend my throttle cable, fired my bike up and it runs like a dream again haha...so if anyone runs into this problem be sure this is the first thing you check....simple mistake but made my life hell for a few days lol...like i said, props to jeff for being awsome!

[armyvet]

ok, bike is fixed, was a stupid problem, took it to jeff at f.a.s.t and he had it running in less then 20 minutes, that guy knows his shit.....the problem was my tors was working....my throttle cable was to tight so my slides were lifted ever so slightly and my tors was trying to kill the engine....i felt like an idiot when he unplugged my tors and loosend my throttle cable, fired my bike up and it runs like a dream again haha...so if anyone runs into this problem be sure this is the first thing you check....simple mistake but made my life hell for a few days lol...like i said, props to jeff for being awsome!

i would still check that jetting,a 270 mains seem lean for ported cylinders.Im at 350 mains with aggressive play port shaved head and toomey filters on stock carbs for now.i may bump up a bit still fine tuning