dirtbike77

nope i didnt notice that.. but that could cause the alot of problems....

i pulled the top end off today to check and make sure the pistons were still in good shape and boy what did i find !!!!! the pistons qwhen up at tdc is still like a inch and a half from the top? on both sides . so im running the numbers off the top of the pistons.. 5271c 795m06500 part #pk150 that suppose to be used with a a 5mm stroker crank? could this be causing severe driveability problems listed in the previous posts?

ive been reading all these post about diffrent backfiring and sputtering problems and i thought maybe the brake sensor up by the clutch lever could be a culprit '' but its disconnected''....... the wires dont have to be cut and spliced together do they? im pretty sure all the tors are disconnected... i think the next move is gonna be the jets. from what i understand the 200 main jets are to to small? i have the air screws almost all the way in to keep it from running mre f'ed up?

i took the flywheel of today to check for a sheared key and it was fine i did hear a lil noise when shaking the flywheel though? so i tried siwtch with another one and nothing still the same? still backfiring at idle and at wot?

were going to go and pick up some 270 or 290 main jets to see if that solves the lean condition.... i dont know the extent of the port job and what affect it would have on the jetting. but hopefully thats what the problem is ! :shrug:

ok im gonna give that a shot... but could that be causing the back fire ?

by the way the jet needles are in the third position... it has 200 jets in it im assuming thats the stock size? the bike has t-5's? port and polish job

all the tors items are removed

i checked the carb slides and im pretty sure there in right . with the halfmoon facing the airbox? wats getting me is the backfiring when u hit the throttle a little bit pass idle... we tryed switching plugs , ignition coils? and swapping from plug cap to the other and still the same thing?

i havent did a copression test as of yet but the timing is stock.. im thinking it has to be something eletrical for it to back fire like that. the little magnetic pieces on the flywheel seem to be pretty clean? i adjusted the pick up coil with a buissness card. and nothing?

i can home today to try some new things... i cleaned the carbs again? cleaned the fuel petcock assembly? put fresh gas in it? and still the same thing? sputters at wot? and even while holding it at a little before half throttle the bike backfires? u can see the flame coming out of the back of the carbs? i adjusted the pick up coil gap? and still nothing? wats else can sause this

im going to replace the spark plugs today and see wat happens? i jus cant figure out wat else it can be?

i also checked for air leaks with carb cleaneer around the base gaskets and the intake manifolds? and none found

hey guys jus rebuilt a banshee for a buddy and now we cant get it to run right. the tors has been removed already. fresh top end rebuild. carbs have been taken apart several times and cleaned. the choke tube is in place. the carbs have been synced as best as possible. air screws are about half a turn to one turn out before it dies out? the bike idles fine .... but no power. its very sluggish to the powerband? almost as if its running off one cylinder? both pipes are smoking normally and both pipes are hot? by the way the bike has new spark plugs? could it be possibility the plugs could've fouled by running it with the tors connected? he has the thumb switch connected and the little black box. i dissconnected both but it cleared out a little bit but still has no power? what's next

well i finally got it.. after pulling the flywheel cover off to check the stator andpick up coil i found some water inside of it... so i decded it to run the bike with the cover off to check if that was the problem... kinda dangerous but i did it... and lord behold it ran like a raped ape... i appreciate everything u guys suggested

well i took the coil of my runnin bansheee... so i know it was a goood coil? i do have the tube in between the carbs... wat other things should i try switching

how big of a jet do u reccomend

not exactly sure but im here in miami? but i dont understand he had the bike witha high compression head, t-5 pipes bored .80 over witha 270 main jet? so for him to put the stock head back on? it should be to rich?

i jus got off the phone with the original owner and he told me when he had the bike he had a high compression head on it... and when he sold it he switched it back to the standard head? the bike is currently bored .80 over? he told me the bike was tuned for the high compression head... no to go back to stock i would think it would richen up alot? but the bike seems to be runnin lean?

i jumped up to 290 jet from a 270 today and it made a diffrence but as soon as i hit third the bike started to loose power and backfire? i pulled the pipes off to look into the face of the piston and they both look n pretty good and it still has right around 130 p.s.i...? the carbs were cleaned again... the plug electrode is a dark carmel? whta could be caussing the backfire ... i pulled the flywheel cover off and a little water leaked out.... everything was corroded but no frayed wires...

ANYONE?

ok i swapped ignotio coils today and i thought is solved the problem and it didnt it still breaks up at high rpms and the bike even backfire's at times.... i also moved the jet needle clip down a notch to see if it richen the condition up a bit and it didnt really do anything... the bike when started idles fine.... even reving it up it sounds fine... when u take off to ride it the bike looses power from about in third gear and it backfires... i cleaned the carbs three times.. dropped the needle down a notch.. new spark plugs, ''with known good igntion coil'' no tors.. wat should i try next.. it almost like the bike is starving for gas? wat about adjusting float hieght

the jet needle postion on the cars is the third notch up from the bottom

what other ways besides jetting that i can probably get the bike to run a bit richer. getting more fuel