NC30 Cutouts (with video)

Letum · L Plate Warrior Joined: 06 Feb 2007 Karma :

Hello!

My NC30 cuts out, usually after any acceleration, revving or engine breaking, although it ticks over fine.

Here's a YouTube video to illustrate part of the problem.

The first time I rev the bike in the video I do so slowly and it revs all the way.
At 10 seconds into the video I snap the throttle open and keep it fully open until the cut-out at the end.

https://www.youtube.com/watch?v=8jj8AIFZ7S0

Any help or speculation would be appreciated!
Thanks! Very Happy

h00dwink · World Chat Champion Joined: 04 May 2006 Karma :

are you turning the bike off?
that doesn't make much sense otherwise
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Letum · L Plate Warrior Joined: 06 Feb 2007 Karma :

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

How long between you snapping the throttle open and it cutting out?

Does it cut out dead or does it splutter out?

Do you know if your bike has a throttle position sensor (look at the wiring diagram)

finpos.

Mooncatt · Brolly Dolly Joined: 08 Dec 2006 Karma :

my mate had a similar problem on his aprilia 125 extrema could be a carb problem maybe??? thats what his turned out to be anyway
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Letum · L Plate Warrior Joined: 06 Feb 2007 Karma :

finpos · World Chat Champion Joined: 13 Sep 2005 Karma :

Maybe I can't see the video Wink

Best guess would be that it's running lean and/or it's got a restricted fuel supply to the carbs (the second could be causeing the first).

Try running the bike off an alternate fuel supply, aka a funnel full of petrol jammed in the fuel line. Make sure any vaccum tubes (e.g. the fuel tap vaccum tube) are blocked off.

Do you have a manual for the bike? Does it mention anything to do with accelerator pumps on the carbs?

finpos.

Finglonga · World Chat Champion Joined: 27 Jul 2004 Karma :

nick606 · World Chat Champion Joined: 12 Nov 2006 Karma :

could be water in the carb this happened with my bike..... or blocked air/fuel filters maybe ?

bike sounds beast though

Harley Godzisz · Trackday Trickster Joined: 15 May 2004 Karma :

NC30's do not have a throttle position censor, nor do they have accelerator pumps on the carbs.

1st of all, do the fuel tap mod (take the fuel tap apart and move the spring to the opposite side of the diaphram.), this will eleiminate any fueling problems now and in the future.

secondly, While you've got the tank off, whip the air box off and look for any plates (carb restriction disk's) that are like a huge washer with a small hole about a quarter of the size of the disk. Remove them if any.

Thirdly, Clean the air filter.

If you still have problems, you have a jet's problem. Try 118 main jets in the front and 120 main jets in the back. That's what i use in my NC30.

Good luck m8 Thumbs Up

Should only take you an hour tops!!! takes me 15 minutes to change jets and get it back to gether.. but then again i did pull my bike apart every weekend!

Cillit-BANG · World Chat Champion Joined: 05 Oct 2005 Karma :

Unless you are racing then avoid the fuel tap mod.

Quite a few people have problems with fuel overflowing from the bowls and entering the oil supply which may result in seizure if left unnoticed. Its ok if you check your float height regularly or turn your tap off every time you stop, but for most it is just a pain in the arse.

I'd agree it is a fuel issue. Have you checked that the vacuum hose is in good condition with no cracks? All carbs are seated properly in their rubbers?