Nc 30 missfire

[scotjell]

Well at present on the m5 with a miss fire thought it may have been fuel so topped up at services luckily. The bike ticks over for quite a while so gain confidence then ride for a mile and starts to splutter. Any ideas please!!!

[skinnydog0_0]

What sort of speed were you doing when it started?
Has it done it before?
How old are the spark plugs?

I would check the vacume hose for defects/splits week points, then check that the fuel line hasn't got a kink in it.
If you have any spare plugs, run the bike if it missfires on one cylinder feel the pipes find out wich one, swap plugs.
See if it misfires in the other cylinder, if it does most likely spark plug.

[scotjell]

Ok thanks for the input. New plugs fitted new vac hose fitted the miss fire is more fuel related than electrical. Whilst the bike was in the back of the recovery van it stank of fuel. Possible crap in the carbs effecting the floats. The bike will tick over you can rev it and suddenly will cut out, but when I was riding it spluttered like when you need to go on reserve so put it on but in my opinion I had only done 120 km's so was confused. Hope this helps.

[skinnydog0_0]

Have you made any mods to the carbs or fueling?
Sorry i am no expert on carbs, have you read any of the other posts on here, about fueling issues?
There are loads, and i am sure there will be an answer for you or at least something for you to try
If not i am sure that someone with more knowladge than me will be along soon enough and offer some advice.

[scotjell]

No mods done to the carbs. Bike has been running fine before this. Luckily I have another nc30 so first thing will be to swop the carbs a little trial and error. Thanks for trying.

[scotjell]

Please guys n gals any input would be apprecited!! Well just to let you know I'm off the M5

[CMSMJ1]

I would go for possibly block fuel tap - the siphons in the ank itself? Does it matter whether you are on reserve or not? Does it go away with a full tank?

Have you a fuel filter inline? Is it clean?

Is the vaccum securely fitted to the correct spigots? Does the vacuum on the tap work 100%

Is the battery fully charged? Does it work better wth no lights on? Have you checked fully the charging system?

One thing at a time...I doubt your carbs are at fault - they either work or they don't.

[scotjell]

1 No it does it on both reseve and on.
2 no inline fuel filter
3 Vacuum is fitted correctly and not sure how you would check it to ensure 100%
4/5 battery and charging system are brilliant on this bike

Does this help or make you think of any other possibilities?

It smelt like the carbs were flooding too much fuel in them would that cause spluttering?

[CMSMJ1]

if you leave the vacuum on the tank but pull the fuel line off the carbs then get someone to help...

Suck the vacuum - fuel should come out the tank and then stop. Might be a good time to point out this is besttested off the bike.... You can use any hose to suck the tap open...and either catch the fuel or get it away from your bike/feet/brew etc.

[scotjell]

OK may have to eat my words regarding the charging system........ Whilst stripping the bike and was going to put the battery and reg/rec on my daily bike which at present has a duff charging system one of the yellow wires was all but come away from the spade. Could this be my problem????