misfiring ?

[stef]

my m600 seems to be misfiring quite a bit.
sometimes a couple of times in the morning, on my 13 miles journey to work.
is that normal ? is there something I should check ?

[Jay]

What year is your bike? Do you have the standard cans fitted or race cans? Has it just started doing it? Does it do it in all weathers or just cold damp weather only - could be carb-icing, comes with a loss of power, especially scary going round corners and roundabouts or trying to avoid a bus!

Should narrow things down :)

Could be a number of things. Have a look at your spark plugs and see what condition they are in, and post that, should give an idea of how your engine is running (fuel riich or lean).

J

[Pedro]

Could be plugs - just had to ditch a brand new pair in mine cause it ran like apig with them. I also found it backfires if the exhaust isn't sealed properly - likely if you got cans.

Ped

[manc skank]

mine misfires because it runs too rich and fouls the plugs, next time it misfires open the throttle fully and if it stops then you know you are running rich! all the advice i have really :p

[stef]

its a 95 model, standard cans, and i just changed the plugs.
the rich mix is not excluded though, because the old plugs were a bit on the black side. But i put that down to the lack of air (the air intakes were turned the wrong way round, facing back.
I hope we are talking the same thing though, when i say the bike misfire, i mean that it makes that really loud 'Bang'
I'll watch for the weather, and see if it still does it in the dry.

[Jay]

The pre electric headed carb Monsters suffer from Carb-icing, mine has the electric heaters and no icing yet, so it could perhaps be that. Has it just started recently, or before you changed the plugs, it could be the plugs as Pedro says.

That carb-icing malarkey happens on non rainy days as well, it depends on the temp and moisture in the atmos. So cold damp, but clear days can be a problem as well.. aah winter

[Pedro]

Mines got oil heated carbs and carb icing doesn't seem too much of a problem - only when warming from cold. Try putting the old plugs back in - I've had two sets now of new plugs that were ****e and I recall others suffering the same.

You might also want to check for air leaks on the inlet side as that may also cause it. Also worth checking stuff like plug caps and leads back to the coils to check they're not perished / split or knackered.

HTH

Ped

[stef]

cheers for all this.
I shall investigate this week end.

[spacemonkey]

IS the bike actually running well when on the throttle? If so it sounds like leaking exhaust pipes somewhere. Wouldn't worry too much, as most of ours do it. Wakes up the car drivers though...