NC30 Nightmare
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Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
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Stockko
- Settled in member
- Posts: 28
- Joined: Sat Nov 07, 2015 7:29 pm
NC30 Nightmare
For the past year and a half i've been trying to figure out why my NC30 runs like trash...
The revs hang this can be very temperamental sometimes it takes minutes or seconds to return to idle (problem seems to worsen when the bike heats up). Also when I give a quick blip of the throttle the bike gasps for air and can sometimes cut out.
I have replaced the rubber boots / clamps, carbs have been ultrasonically cleaned and synced, new spark plugs, adjusted valves.
Any ideas? Really is driving me crazy, I've hit a brick wall.
The revs hang this can be very temperamental sometimes it takes minutes or seconds to return to idle (problem seems to worsen when the bike heats up). Also when I give a quick blip of the throttle the bike gasps for air and can sometimes cut out.
I have replaced the rubber boots / clamps, carbs have been ultrasonically cleaned and synced, new spark plugs, adjusted valves.
Any ideas? Really is driving me crazy, I've hit a brick wall.
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Morespeedvicar
- Site Supporter
- Posts: 837
- Joined: Thu May 01, 2008 1:37 am
- Bike owned: Fzr400, NC30, CB50J, SS50Z KLR
- Location: Grimsby
Re: NC30 Nightmare
Still sound to me theres a blockage in the idle circuit somewere. have you tried squirting wd40 or something through all the passages? Or maybe theres a tear in the carb diaphragms or something?
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magg
- Senior Member
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- Joined: Mon Sep 20, 2010 11:55 pm
- Bike owned: VFR400
- Location: Blue Mountain NSW Australia
Re: NC30 Nightmare
Does it settle a steady idle if left alone for a time.
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royster81
- NWAA Supporter
- Posts: 2509
- Joined: Wed Apr 30, 2008 8:04 pm
- Bike owned: VFR400R-L NC30 CBR400RR-R NC29
- Location: Belfast,Northern Ireland
Re: NC30 Nightmare
Could the slide/slide rubber have cracks or tears in then? Or the slide hope is to big?
It's not having what you want but wanting what you've got....Loud ,Proud and Modified ....
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Neosophist
- Moderators
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- Joined: Fri Jul 04, 2008 1:01 pm
- Bike owned: CBR954
Re: NC30 Nightmare
Another set of carbs from a known working bike would be handy in a situation like this.
Hanging revs is almost always the classic lean idle symptom.
Usuaully caused by poorly fitted carbs / bad sealing rubbers.
Problem with idle circuit
Mixture / pilot screws out.
Valve clearnaces / carb balance way off.
Does it change as the engine heats up?
Carbs are pain to fit, are they fully seated in their rubbers... i once went to have a look at an nc30 and the owner had put the carbs on and off like 20 times but wasn't sitting them in right.
Antoher one with similar issues was the balance was way off.
spraying carb clearn liberaller aroudn the rubbers when its hanging will help diagnose an air leak.
you also have carb balance screws / vaccum fuel tap take off hose... they can also leak air and cause above symptoms
Hanging revs is almost always the classic lean idle symptom.
Usuaully caused by poorly fitted carbs / bad sealing rubbers.
Problem with idle circuit
Mixture / pilot screws out.
Valve clearnaces / carb balance way off.
Does it change as the engine heats up?
Carbs are pain to fit, are they fully seated in their rubbers... i once went to have a look at an nc30 and the owner had put the carbs on and off like 20 times but wasn't sitting them in right.
Antoher one with similar issues was the balance was way off.
spraying carb clearn liberaller aroudn the rubbers when its hanging will help diagnose an air leak.
you also have carb balance screws / vaccum fuel tap take off hose... they can also leak air and cause above symptoms
xivlia wrote:i dont go fast on this bike so really do not need a rear brake.. /
vic-vtrvfr wrote:Ask xivlia for help, he's tackled just about every problem u could think of...
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Stockko
- Settled in member
- Posts: 28
- Joined: Sat Nov 07, 2015 7:29 pm
Re: NC30 Nightmare
Thanks guys for your advice.
Yes it seems to get worse once the bike heats up. Indeed could really do with some working carbs, just been offered 'meh' condition carbs for £110 which supposedly run well, debating weather to purchase.
Had the bike running with the tank off, noticed one diaphragm doesn't seem to be moving when revved?.. Shall check for tears etc next.
Yes it seems to get worse once the bike heats up. Indeed could really do with some working carbs, just been offered 'meh' condition carbs for £110 which supposedly run well, debating weather to purchase.
Had the bike running with the tank off, noticed one diaphragm doesn't seem to be moving when revved?.. Shall check for tears etc next.