Cylinder 2 misfire

[QBTO]

Got a misfire on cylinder 2
It runs rich (black plug) so much it will eventually stop the plug sparking.
You can hear it running rough at tickover, swapped the injector with number 4 no difference.
Swapped the ht leads on 2-3 over still misfiring.
Bike has Yoshi cams and a PC3usb, I've tried unplugging the PC3 and running without still no joy.
Bike also won't rev past
5-6000rpm underload
No FI warning lights showing

Any ideas ?

[Hooli]

I assume you've swapped the plugs around too?

[KiwiCol]

Coils?

[gsxbarmy]

Checked valve clearances?

[QBTO]

Swapped plugs, changed plugs and swapped HT leads on 2-3
Swapped injectors

Not checked valve clearances yet or checked compression both on my to do list.

Was wondering if it could be throttle body balance ?

[KiwiCol]

Yeah could be, but it'd have to be way out and just #2. Definitely worth a look though.

[QBTO]

Ok so took the cam cover off and the cam timing is a tooth out !
I have 25 rollers between alignment marks instead of 24 as stated in the manual.

[gsxbarmy]

Hmmm might explain it.....doesn't help anyway.

Lets hope that putting it right solves your issue

[Hooli]

Cam timing being over advanced on the inlet side makes it lean. Then it runs hot & it can drop valves, had that once on a fiesta...

Hope not in this case though.

[rollerfish01]

Ok so took the cam cover off and the cam timing is a tooth out !
I have 25 rollers between alignment marks instead of 24 as stated in the manual.

Hi QBTO, do you solve the problem by adjusting the cam chain back to normal setting ?

[Andre]

How can the cam timing come out of spec?

Haven't looked this up in the manual but it doesn't make sense that it would only affect one cylinder. Right?

[lawrie]

I concur with the above, if the cam timing is out for one, then its out for all, every cylinder MUST receive the same timing.
If the plug is black (rich) then the injector/fuel side must be working or it would be a neutral colour.

  IF  ( highlight 'IF ) )everything has been swapped around to eliminate all possibilities, then it only really leaves piston, ring/s, bore or valves, all of which are just about bombproof, me, i'd look at the valves, possible burnt exhaust valve. 

Try a compression test before popping the head!!