misfire at 5-6000 revs

[monksey]

hi has anybody come across this problem ? i have got a fz1 2003 which has been fine so far but i have been for a ride today and it was ok but after about 20 miles i have a misfire at 5-6000 revs and it wont rev through it , the more i pull the throttle back the worse it gets, if i pull the clutch in at the time it will rev ok or if in neutral it will rev ok ? thanks , ps it has done 20000 miles

[allanmac]

Is it definately a misfire or does it just go really flat? Worth checking the exup valve is opening. Mine was siezed shut when i bought it and wouldnt pull past 6k.
Cheers Allan

[Falcon 269]

And check nothing's being sucked into the airbox lid snorkel ...

[monksey]

hi def a misfire i will go and check the air intake thanks

[monksey]

intake ok so will read up on checking exup valve cheers, steve

[bash62]

turn ignition on and watch rev counter .if needle goes to 7000 revs its the exup.but for sure check air intake under seat too as mike says
cheers
bash

[monksey]

ok thanks everybody i will have a look at valve tomorrow , the rev count doesnt go to 7000 when i switch ignition on though ,steve

[monksey]

sorry i just thought like i said it revs ok when not engaged in gear is this normal for exup probs

[allanmac]

Hi Steve
Mine wasnt showing the 7k tacho error when i turned the ignition on and reved fine in neutral but hit a wall at 6k ish. turned out the valve was siezed and the cables were too slack to stop the servo turning even though the valve wasnt moving. Worth checking even if only to rule it out.
Cheers Allan

[1967fazer]

Mine did the same, wouldn't rev beyond 7000rpm on mine, but then the exup valve wasn't seized just badly adjusted! Didn't get the rev counter warning display either. Well worth checking the exup valve, but watch out for the bolts holding it on!

[unfazed]

Looks like an EXUP issue I came across some time ago when the upper cable at the EXUP valve broke because it was rubbing  off the cover. Previous owner/mechnic may have bent the cover and that was what caused it.  The 7000 rev indication did not show as the EXUP motor was working happily but doing nothing.

[monksey]

thanks everybody sorry i been away for a while , i have had a look and the cables to the exup where slack so i have tightened them and had a short ride and it seemed ok , i will try a longer ride at weekend , i noticed that if you tighten them too much you get the 7th tacho fault , thanks again chaps, steve