need help guys im stumped!

[4milstrkr]

i have a 96 banshee, procircuit exhaust, ported, 4millcrank, 18cc domes, nology profire coil, bored .40 over, rad valve, rmstator ignition, my bike has a bad high end miss in 5th and 6th gear. it pulls harder at 1/4 throttle in 6th gear than at full throttle, and the jetting is perfect what could it be????????

[coryv4]

i have a 96 banshee, procircuit exhaust, ported, 4millcrank, 18cc domes, nology profire coil, bored .40 over, rad valve, rmstator ignition, my bike has a bad high end miss in 5th and 6th gear. it pulls harder at 1/4 throttle in 6th gear than at full throttle, and the jetting is perfect what could it be????????

first off ive heard the rad valves accually make less hp maybe you running a lil rich on the main stator might be going bad it could be a number of things give some more info whats ur compression and hows ur plugs look

[4milstrkr]

plugs look good, about 170psi

[coryv4]

plugs look good, about 170psi

i think it might be a spark issue or maybe dirty filter?

[4milstrkr]

filter is clean what could cause a bad spark, i am also having to shrink my plug gaps

[Rotax Raptor]

What carbs are u running and jetting.

[AKheathen]

ok, and just what fuel are you running. what kind of porting? if you are only getting 170 cranking 18's on a 4mill, it kind of sounds like you are high rpm ported, or 10k+ elevation. if it's ported something like dune/drag, then none of your setup matches the cyls. now, on the other hand, the rmstator ign. could be at fault. whatever cdi you run needs to be able to support the nology, too

[dirtydownunder]

if the jetting is perfect, id check all the ignition resistances (plug caps, pickup, charging coil and ignition coil/leads) and check the pickup gap. RM stators have a pretty bad name, so inspect that (like bad wires or something burnt), have you got a stock stator you can try ?

 

when did the bike start doing it ? were new parts fitted or anything ?

[4milstrkr]

i really noticed it after i put the 18cc domes in the bike, im runing 114 octane fuel, stock carbs with a 340 main, 800ft elevation. and the porting i did myself just narrowed the bridges and smothed all the rough edges

[coryv4]

i really noticed it after i put the 18cc domes in the bike, im runing 114 octane fuel, stock carbs with a 340 main, 800ft elevation. and the porting i did myself just narrowed the bridges and smothed all the rough edges

did u run your port job before you baught the 18s?

[4milstrkr]

before

[Rotax Raptor]

With 340 mains your putting quite a bit of fuel through some small carbs. You have to have enough air to burn the fuel you're drawing in. Just a thought. Don't go buying new carbs without getting some feedback from others running the same size motor.

[dirtydownunder]

does sound kinda fat, are you running a spacer plate or cut 4mm domes ?.

 

due to the increased compression, that puts more load on the engine, maybe enough load to break down the spark, it happens. can you adjust your timing ? if your advanced, you could retard it 1-2 degree's to see if that helps. maybe try gaping your plugs to .025".

 

worst case throw ya old domes in there.