NC30 carby jetting - DIY guide

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ChowderV4
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Re: NC30 carby jetting - DIY guide

Post by ChowderV4 »

ok the 1 millionth time this has been asked.

i have just put a half system on and re jetted 118 front and 120 rear
and its a little fluffy around 5 1/2 to 7 grand, any way of curing this
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CMSMJ1
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Re: NC30 carby jetting - DIY guide

Post by CMSMJ1 »

Have you added an extra shim? If so, remove it... ;)
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ChowderV4
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Re: NC30 carby jetting - DIY guide

Post by ChowderV4 »

didn't get the needles out....ran out of time .

shall check it out when i have the carbs off next.
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Re: NC30 carby jetting - DIY guide

Post by Neosophist »

Fitting the shim raises the needles slightly, which in turn richens up your mid-range, which is usually what is causing your flatty spot.

Try this to solve it!

If you get the tank off you should be able to remove the tops of the carbs with them still on the bike?
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CMSMJ1
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Re: NC30 carby jetting - DIY guide

Post by CMSMJ1 »

Neosophist wrote:Fitting the shim raises the needles slightly, which in turn richens up your mid-range, which is usually what is causing your flatty spot.

Try this to solve it!

If you get the tank off you should be able to remove the tops of the carbs with them still on the bike?

You can get the needles no worries without removing the carbs...
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samace
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Re: NC30 carby jetting - DIY guide

Post by samace »

I just stripped my carbs and had 115/118 on a standard pipe. The bike hunts on tick over any Ideas ?
Need to put the second shim in as I have only just read this.


:roll:
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Cammo
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Re: NC30 carby jetting - DIY guide

Post by Cammo »

samace wrote:The bike hunts on tick over any Ideas ?
That's usually a sign that they need balancing.
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Jono035
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Re: NC30 carby jetting - DIY guide

Post by Jono035 »

samace wrote:I just stripped my carbs and had 115/118 on a standard pipe. The bike hunts on tick over any Ideas ?
Need to put the second shim in as I have only just read this.


:roll:
I asked a local NC30 expert about switching from the 115/118 jets on my bike and he said that unless I was dead set on doing a complete rebuild to leave them as they would have worn slightly with time/kms and would be running richer than new. He seemed to think that on a high-km bike like mine (96,000) that I could very easily go to new 118/120 jets and end up leaner than it is currently.

Don't know if that helps at all.
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Re: NC30 carby jetting - DIY guide

Post by samace »

All carbs balanced mixture screws set at 2 1/2 turns is that ok ? Ran ok before I stripped carbs ?
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Re: NC30 carby jetting - DIY guide

Post by anp »

A real good read that I could do with some additional info

I have aquired a UK model NC30 that has done around 7000 miles problem is it was last used in the 1995 MGP it runs but the carbs are so blocked in fact they are the worst I have ever seen the jets are blocked & surrounded in a tar like substance which I am slowly clearing off what I need to know is what is the fixed tube that is shown quite clearly in the noted picture in the article above the jets I have a feeling it should be clear can anyone tell me what it is ?

thanks

Paul

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