turboglenn

okay, i'm working on an F4i for a girl i know... i rode it home limping on a few cylinders and called it a night last night. Today i put in new plugs ( the old ones were fouled ) and it ran perfect when i fired it up still partially dis-assembled. After i put it back together and got the tank adn everythign snapped up, i started it and it fouled the center 2 plugs immediately. I took it down the road to try and "clear it out" a bit, and under WOT the bike sputters and bogs, then once it's up to 10k or so the other 2 cylinders will light up and the bike will haul a$$. but as soon as you let beck out of it the plugs are not firing and it's limping along.. any ideas? there's no FI light and nothing seemed out of the ordinary when i looked it over.

is there something that might cause the center plugs to die out? maybe something electrical like a sensor or something ( never worked on an F4i, but i am a very competent mechanic )

this baffles me, supposedly it just started acting like this one day, we've changed gas and everything and it still wont' run right at all.

BTW.. i know it;s the center plugs because i'm spraying the header with a water bottle and those 2 are cold enough that water won't burn off them

Street Warrior

throttle body sync? maybe injectors

turboglenn

i synced the TB's for the girl a while back when the bike was running fine so it's not that.

I was thinking the injectors might be clogged, but if they're letting enough gas through to foul plugs they would have to be so dirty they were stuck open. And since there's 2 that are on the same ignition bank i'm thinking it's something deeper and related to the ignition system.

Street Warrior

yeah I dunno what I was thinkin, it would have to be electric. Maybe try switching coils around and see if anything changes? or a new ignition harness. or maybe ecu? it doesn't have a pc does it?

binder929rr

loose electrical connections maybe or the throttle bodies are way out of sync. i would take apart all electrical connections and use dielectric grease on them and make sure they have good contact. definately make sure you are getting good spark to the plugs.

then i would have the throttle bodies synced. you might be pouring fuel into the center 2 cylinders causing them to foul (if they are even sparking)

the gnar

check the compression in all the cylinders. had the same **** going on with my 02. it started off not so bad and then everytime i rode it, it got a little worse. no FI light, changed plugs, would work ok in low or high RPMs but mid was just bogging. turns out there is only 90 psi and i need a top end rebuild.

turboglenn

okay, it is still the center 2 every time. the coils are sparking good on good plugs, but it will still foul out in no time. swapped coils around and still the same results. it's pouring so much fuel in the motor that it's litterally just sending it out the ehaust as white smoke ( and a lot of it ) it's burned through a half tank in 2 very short test rides ( maybe 30 miles altogether )

still starts and runs right away, but nothing in those 2 holes. I"ll pull a compression test tomorrow or on the weekend, but they seem fine from general inspection.


The bike is completely stock ( no pc ) so i'm begining to think it's something in the sensors making it think it needs a ton of injector pulsewidth or the computer is possibly bad ( is that very common on F4i's?? ) The injectors are shooting so much gas it's like they are actually sticking open. I might take them in for an ultrasonic cleaning, but something tells me that's not going to solve it... this one has me really scratching my head...hopefully some one has ran intop this same thing and it not being compression related like yours was 600rrizzle.

each time i pulla polug out and run the motor to pump the cylinder clean it shoots out at least a few spoonfulls of raw gas WAY too much for anything that motor should require from the injectors

binder929rr

eh, i don't see that being a compression problem. with that much fuel and low compression due to ring wear you'll have gas in your oil.

get the throttle bodies synced, could have had something go terribly wrong there. also, you can check your fuel pressur regulator (i don't remember how off the top of my head, it's in the manual), but you coudl just buy a new one for 20$. i would recommend getting one and putting it on to test to see if that's the problem. they have tons of problems with the pressure regulator, but normally they restrict flow when they go bad. never know though.

turboglenn

it's definately not a sync issue, if i were to manually sync them with a small guage wire or drill bit they'd be pretty much dead on ( i've double checked tehm with feeler guages)

as for the regulator, that's a good call. old ford pickups use to have major issues with them, they would get a hole in teh diaphram and leak extra gas back into the manifold via the vacum line that controls it. think i'll go check that now

keep the ideas comin, i wann get this bike back to it's owner and get paid so i can get some more riding in before the cold weather gets here ( and it''s creepin in fast )

anyone know how to get this thing in diagnostics mode to check the FI system out? i don't have a manual on hand yet for this thing..also want to check teh MAP sensor if anyone knows how

turboglenn

exactly the problem !!!!!!!!!!!!!!!!!!! woohoo...thanks!

turns out it's leaking just like i said a ford pick up would ( gas through teh vacum line) and that line runs into the middle two cylenders ( the ones i'm fouling) and it was full of gas as well ...do you know where they sell em cheap or do you have a part # or link?

thanks again
Glenn

binder929rr

they are only about 20$ from the dealer.

i usually go to www.bikebandit.com or www.ronayers.com if i wanted to go online......but i usually go to the local dealership.

turboglenn

ronayers wants 52 + shipping and bikebandit wants 62 + shipping. I'm gonna call teh stealership here in a bit and try adn get something done.

thanks again for the help