nc21 performance prob. above 4k rpm.

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tragos
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Posts: 15
Joined: Sat Apr 17, 2010 9:29 pm
Bike owned: vfr nc21
Location: greece
nc21 performance prob. above 4k rpm.

Post by tragos »

Hi! 8-)

My nc21 has poor performance after passing 4k rpm.
I dont know what happened. something like can't breathe.

At idle it works ok, not hanging. all starts after passing 4k rpm.

any advices?

valve clearences?
main jets?

sorry for my bad english...
Neosophist
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Bike owned: CBR954
Re: nc21 performance prob. above 4k rpm.

Post by Neosophist »

Did it suddenly start?

It's not likely to be main jets if it just start.

Electrical system (is battery charging?)
fuel system.. is vaccum pipe from tank to cylinders ok?
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...
tragos
Settled in member
Posts: 15
Joined: Sat Apr 17, 2010 9:29 pm
Bike owned: vfr nc21
Location: greece
Re: nc21 performance prob. above 4k rpm.

Post by tragos »

yes it starts suddenly...
battery charging ok.
vaccum pipe ok... i dont know what to do...
Neosophist
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Re: nc21 performance prob. above 4k rpm.

Post by Neosophist »

not likely to be jets then.

Was it standing a long time before the problem start? if it was not then carburettor problem is not likely.

Have you tested electrical system with multimeter? They are known to have problem.

Test the battery voltage at idle and at 5000rpm, with and without headlight
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...
tragos
Settled in member
Posts: 15
Joined: Sat Apr 17, 2010 9:29 pm
Bike owned: vfr nc21
Location: greece
Re: nc21 performance prob. above 4k rpm.

Post by tragos »

No it's not standing for a long time.
I test the battery tomorow... I have fitted bigger battery from a yzf r1 (jel) 10A. I dont do it right?
Neosophist
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Bike owned: CBR954
Re: nc21 performance prob. above 4k rpm.

Post by Neosophist »

tragos wrote:No it's not standing for a long time.
I test the battery tomorow... I have fitted bigger battery from a yzf r1 (jel) 10A. I dont do it right?
the smaller battery is ok, the problem is usually the charging circuit stops working so the battery doesnt work properly
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...
tragos
Settled in member
Posts: 15
Joined: Sat Apr 17, 2010 9:29 pm
Bike owned: vfr nc21
Location: greece
Re: nc21 performance prob. above 4k rpm.

Post by tragos »

i still have tha same problem, and now not fairing at all..

no spark at any cylinder....
magg
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Joined: Mon Sep 20, 2010 11:55 pm
Bike owned: VFR400
Location: Blue Mountain NSW Australia
Re: nc21 performance prob. above 4k rpm.

Post by magg »

Are you using original battery still, what is the voltage.
tragos
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Posts: 15
Joined: Sat Apr 17, 2010 9:29 pm
Bike owned: vfr nc21
Location: greece
Re: nc21 performance prob. above 4k rpm.

Post by tragos »

yes i am on original battery now.
voltage 14.5v at 5000rpm, a litle bit lower at idle...

i found water in my spark unit!! i think thats the problem!

is there a way to fit a nc24(rh) spark unit to my nc21(rg)?

nc24 has 3 wires les than the nc21.

nc21 has a camshaft sensor.
Neosophist
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Bike owned: CBR954
Re: nc21 performance prob. above 4k rpm.

Post by Neosophist »

tragos wrote:yes i am on original battery now.
voltage 14.5v at 5000rpm, a litle bit lower at idle...

i found water in my spark unit!! i think thats the problem!

is there a way to fit a nc24(rh) spark unit to my nc21(rg)?

nc24 has 3 wires les than the nc21.

nc21 has a camshaft sensor.
I dont' think you can fit it easily.. get an NC21 spark unit
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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