deja vu !

[ade the blade]

ok guys and gals, i have been reading the stuttering thread very closely and thought it time to ask for your help with my partners 600. if it was mine then i could just be patient and tinker whenever but its the bosses, so the clocks ticking  

ok very quick rundown on prob....bike starts on the button ( even cold ) , ticks over lovely. give it a good handful and it bogs and i mean bogs down so bad until throttle is released. tried a road test, bike will not under any circumstances lift above 4000 rpm giving a top speed at present of 50 mph...........just over scooter territory :eek . this is even gently easing the throttle open, no hope in hell of whacking it open. there is a definite stutter when throttle is eased open and hand is placed near end pipe. ok enough of symptoms for now quick rundown on what i have checked, replaced ect. bear with me. cheers
fuel system........new clean (?) fuel in tank. petcock filter clean. all fuel lines cleaned and compressed air blown through. new fuel filter. fuel pump tested and working correctly. carbs dismantled and cleaned thoroughly 4,yes,4 times. all spotless and adjusted correctly. ( 2 turns on pilot ) even tried those set at 3 turns out and up to 1 turn out. float heights all set in spec. no difference!!!!!!!!!!!!!
ignition.......tested right from pick up coil to spark plugs with multimeter. ( all resistance readings in coils (primary and secondary) circuits within spec). fitted new plugs. and plug caps. everything in theory is fine. even checked valves in desperation ( well inside spec only 11500 on clock ( 2000 bike ).
finally as last resort, even ran a seperate fuel supply from a bottle directly to carb rail ( bypassing pump and even filter ). still no difference whatsoever !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
so its over to you fellas for input pretty please.all suggestions greatfully received. already got the ak47 and sidewinders ready so dont include those !! thanks chaps. cheers Ade.......will try and get a vid up at some point. ( fingers crossed )

[Fazerider]

Air filter?
Anything obstructing the intake to the airbox?

[ade the blade]

hello mate.....air filter cleaned and re oiled ( k + n ). no obstructions. did spray a small amount of carb cleaner in when `bogging` and it did redline briefly and then return to usual crap running :'( good try though. oh even reset tps ( 5 times for what its worth :\ ). anything else come to mind ?

[keno]

anything else come to mind ?

[/size]
[/size]Tank breathers come to mind

[ade the blade]

hello mate.........checked those. all clear and no vacuum hiss when opening fuel cap. good try . anything more ? prepared to sell some body parts if needs be. :lol

[Panthor]

I once had a problem like this on a 125 scooter, ended up being the choke was jammed on.

[ade the blade]

thanks for that mate.........all plungers and choke assembly checked umpteen times. all operating as normal. 

[red98]

i can understand you taking the carbs off 4 times...it does sound like a carb problem.are the diaphrams ok ? you mention k+n filters have they been on long, are the jet sizes correct,do you still have the origanal filter that you could refit to see if it makes a difference

[ade the blade]

evening mate.....thought i`d join the stuttering club !!! . diaphrams are fine. sliders ect fine. bike is not fitted with pod filters. direct oval replacement for stock filter. jets are as standard. bike has been running fine for last 2 yrs with this filter ect fitted, its only now all of a sudden that these gremlins have struck !! :\ . ok, prepared to put right leg on fleabay !

[Fazerider]

The squirt of carb cleaner getting the revs to rise sounds as though we're back to fuel starvation as the most likely cause of the problem. At least it's not the ignitor restricting the revs.
You must know your way around the carbs better than me by now so I'm reluctant to suggest silly things like carb slides jamming or the throttle control not able to turn the butterflies the full 90º. But, on the other hand, I can't think of anything else at the moment, sorry.

[ade the blade]

hey folks, red98 has just given me a brainwave. could the k+n filter be working too efficiently and leaning out the mixture too much ? remember, i sprayed carb cleaner into air intake and bogging stopped and bike redlined for a split second ( assuming carb cleaner acted as `fuel` for a second thus cancelling out extra air intake? am i getting too desperate now or does that make any real sense ? cheers Ade. oh and yes red, i do have original kicking around somewhere. ( compulsive hoarder me !)

[ade the blade]

sorry for the overlapping post fazerider.

[griff86]

What condition are the inlet rubbers in? Spray some wd40 around them when on tickover and see if the revs rise, could be an air leak somewhere.

Also on tickover are all the downpipes the same temp?(careful doing this though).

[red98]

we could have the same problem,looks like you`ve covered everything in the carbs and the remote fuel supply has ruled out pump,filter and breather pipes,you have gone one step further than me with the checks on the coils,these things rarely fail,iam at a standstill with mine until the needle jet arrives,if this does not work ,ill be making further checks.....did you check the needle jets when you had the carbs apart ? sounds like your down on power all round and not just on one cylinder or could it be running on 2 and have a dodgy coil thats not showing up on your test ?.................thinking aloud,not much help,i give it some more thought....dont let it get you down  

[ade the blade]

another idea has come into my fried bonce :lol  if i partially (just for testing purpose only), block off part of the air intake, then that in theory would richen the mixture up a bit and smooth out running issues wouldn`t it? (please say yes). thus confirming engine is running lean !!or am i just dreaming and this idea is a load of sweaty bo$$cks !!!!

[red98]

put the old filter in and see...wont cost anything....i have k + ns on my suzuki x7, jetting has to be spot on to get the best from them.

[griff86]

I had a bike in with similar issues.

Turned out to be the engine sucking in to much air due to leaking inlet rubbers and them being a poor fitment to the cylinder head.

[ade the blade]

griff mate, rubbers were fitted new last sept and i`m one step ahead of you with the leak testing sorry. thanks for input anyway mate. appreciate it as i do with everyones comments so far

[Dead Eye]

Just my quick two scents but I think someone mentioned that Fazers tend to run with a rich mixture as standard so the K&N should help more than hinder. I have one on mine (fitted last month) and it's definately got a bit more power BUT I did renew the exhaust system at the same time...

Actually, could restriction on the exhaust cause the issue? I am not a mechanic in any sense of the word. Hmm, though the Carb cleaner kinda puts a hole in my theory right?

[griff86]

Are the float heights correct?