Bikes suddenly misfiring and sounds rough.

[lllN30lll]

Riding along and the exhaust was popping a little more than usual, then the engine not changed and it sounded like it was running on 3 cylinders. Luckily I was only a few feet away from home.


Any ideas what the problem could be, it won't rev cleanly and won't go over 3-4000 rpm.

 

[ekdg]

your right it sounds like its running on three., Do you have a pcv fitted? If so have you checked the connectors at the injector end? if you don't have a PCV then start with the basics. coil, plugs If PCV is fitted and all connected up i would try the bike without it. this should also indicate fuelling problem.

 

[lllN30lll]

Yes mate got a PCV. Getting to the coils is a ball ache. And I can't find a guide to removing the airbox.

I Might remove the PCV tomorrow to see if that's at fault.

 

[ekdg]

i would go pcv first check the connections as you go

 

[Hopper]

She's dosnt sound good bud !! Is that a slight knock/rattle from the engine too ? Maybe revving it like you were isn't the best idea...



Least it doesn't sound like this on !!

 

[UrbanRacer]

Listening to that it sounds like an electrical problem rather than mechanical.
I didn't know you had a PCV, i would certainly start there and see how it goes once its disconnected.

 

[Beamish]

I agree, does sound electrical on the vid, like an ecu restriction. If it is the same fitment as other bikes ( i havent fitted one on the S1K) but on other bikes bad soldering on the throttle position sensor can cause grief. The others are plug in but the TPS is sometimes a splice. I could be wrong and someone on here that has fitted on to the bm will no doubt put me straight or agree :0)

 

[Marcus81]

I had a problem where after some work I left the plug to the servo on the velocity stacks loose and it lost connection giving similar symptoms

 

[Ducky]

I don't like the sound of that, shame you're not closer and I could plug in my diags. While it's idling just lick your finger and dab some spit on each of the exhaust headers, look see where it doesn't dissolve so you know what cylinders aren't firing properly.

 

[andybarsblade]

While it's idling just lick your finger and dab some spit on each of the exhaust headers, look see where it doesn't dissolve so you know what cylinders aren't firing properly.

Peasant

 

[Ducky]

Haha, I'm old school! That's a nice bit of kit what does one of them retail for?

 

[Shug]

Bet a packet of hob-nobs on a loose/dodgy connector rather than anything more serious. That's one of my problems with piggy-back stuff like Power Commanders in general - you multiply the connectors, so multiply the chances of a loose one popping up.

 

[ekdg]

Bet a packet of hob-nobs on a loose/dodgy connector rather than anything more serious. That's one of my problems with piggy-back stuff like Power Commanders in general - you multiply the connectors, so multiply the chances of a loose one popping up.

My thoughts exactly, either a injector connector or the tps connector as you are relying on a sharp pin being screwed into a wire.

Andy nice heat tracer...

 

[lllN30lll]

Cheers, I now know that cylinder 4 isn't firing. The S1k is incredibly difficult to get the the coils because they decided to mount the ECU onto the top of the airbox and all the harnesses stop me removing the airbox. I can see the coils but they all look held down with a bar.

Mechanics picking it up on Thursday

 

[Hopper]

Should be an easy fix.

 

[Ducky]

That bar you can see, just takes the gases from the head and feeds them back into the air box, it doesn't affect the coils.

It's not too bad removing the air box, but you have to be patient and take your time.