NC30 lack of power above 7k revs
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- bikemonkey
- NWAA Supporter
- Posts: 1521
- Joined: Tue Dec 27, 2011 12:33 pm
- Bike owned: 92 NC30, 90 VFR750
- Location: Oxfordshire
Re: NC30 lack of power above 7k revs
Drilling the slide is only to do with throttle response.
Raise the needles too much and you get a flatspot due to it being too rich.
Have the needles too low and you also get a flatspot due to it being too lean.
The air/fuel ratio needs to remain on the right ratio constantly throughout the rev range for the bike to run perfectly.
Raise the needles too much and you get a flatspot due to it being too rich.
Have the needles too low and you also get a flatspot due to it being too lean.
The air/fuel ratio needs to remain on the right ratio constantly throughout the rev range for the bike to run perfectly.
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- Settled in member
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- Joined: Sun Nov 04, 2012 9:17 pm
Re: NC30 lack of power above 7k revs
Ok i will try no washers on the needle and see how i get on.
- bikemonkey
- NWAA Supporter
- Posts: 1521
- Joined: Tue Dec 27, 2011 12:33 pm
- Bike owned: 92 NC30, 90 VFR750
- Location: Oxfordshire
Re: NC30 lack of power above 7k revs
What do you have on there now?
Go down in 0.5mm increments, might save you from taking the carbs off more than once
Go down in 0.5mm increments, might save you from taking the carbs off more than once

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- Settled in member
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Re: NC30 lack of power above 7k revs
There was the standard half mil ones on to begin with then i went up to 1mm washers with no difference
- jetblack
- Site Supporter
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- Bike owned: '89 NC30 SEED
- Location: Nottingham
Re: NC30 lack of power above 7k revs
Just get it on a dyno. Anything else is guess work.
It don't matter if i'm fixin' it or ridin' it.
xivlia wrote:sorry about that whole thing jetblack, i just got confused about the whole thing, and i didnt mean any disrespect to you.
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Re: NC30 lack of power above 7k revs
Sorry for the delay updating, been away to the northwest 200 and only got time at the weekend to get back to the bike. I have now removed the washers altogether on all needles but this has made no difference at all. It has been suggested it is running too rich and not lean but having gone from standard jets to bigger it did improve upper rev range.
- Cammo
- Site Supporter
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- Joined: Thu May 01, 2008 12:35 am
- Bike owned: NC30
- Location: Melbourne, Australia
Re: NC30 lack of power above 7k revs
My guess is that it's running lean, typical symptoms when too much air (or not enough fuel) is getting in.
You sure you have the stock rubber flap in place? Part 15 here: http://www.akhara.com/nc30/nc30parts/files/51.htm
Stock needles fitted (marked 'J51')? Stock pilot jets fitted (#35)?
Something's amiss...
You sure you have the stock rubber flap in place? Part 15 here: http://www.akhara.com/nc30/nc30parts/files/51.htm
Stock needles fitted (marked 'J51')? Stock pilot jets fitted (#35)?
Something's amiss...
"It's just a ride" Bill Hicks
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- Settled in member
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- Joined: Sun Nov 04, 2012 9:17 pm
Re: NC30 lack of power above 7k revs
Just like to thank everyone with suggestions for the vfr but no longer need to worry. An ershole in a Nissan Quashqi pulled out in front of my son last night resulting in the bike going under the car and my son into the wing. He is ok a bit sore today but the bike is dead. Once insurance company have sorted things out i will list for spares if anyone interested.
- CMSMJ1
- Moderators
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- Joined: Thu May 01, 2008 9:42 am
- Bike owned: NC30-No9
- Location: Chesterfield, United Kingdom
Re: NC30 lack of power above 7k revs
Shit..
Glad your lad is OK - that is what matters.
Glad your lad is OK - that is what matters.
IMPERATOR REX ANGLORUM
The V4 is the law..
NC30 - No9 - my old mate
The V4 is the law..
NC30 - No9 - my old mate