NC30 main jets

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DougBee
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NC30 main jets

Post by DougBee » Wed Apr 06, 2016 7:39 am

I've read and done all of the rejetting guide and last night was looking through my factory manual and spotted something wrong. The jetting guide says "all UK bikes (2 x 120f, 2 x 122r).". The manual says 122/120 front/rear. This seems to make sense, the front cylinders run slightly cooler so need a bit more fuel.

I could be wrong, anyone tell me if I am (reckon that'll happen pretty quick anyway!) but does that mean that when I up jetted I should have gone 120/118 front/rear not the other way around?

Neosophist
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Re: NC30 main jets

Post by Neosophist » Wed Apr 06, 2016 10:03 am

parts fiche also shows larger jets at the front.
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DougBee
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Re: NC30 main jets

Post by DougBee » Wed Apr 06, 2016 10:26 am

Yep UK bikes definitely seem to have bigger jets in the front, but to make it more complicated I checked the Japanese market parts list, they run 115 front and 118 rear so the opposite way around. I always found most V engines if they have a different sizes put larger jets to the front cylinders.

Anyway bikes going to the dyno today so I'll speak to them about it and I'll see what they think.

DougBee
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Re: NC30 main jets

Post by DougBee » Thu Apr 14, 2016 2:20 pm

Well the dyno seems to say the jetting is about right, haven't been to pick up the bike but spoke to the guy and it's doing about 59 at the wheel. Said a touch rich at the bottom but literally a fraction and top end is so close it wouldn't need changing for road use, if it was racing he suggested 1 size up or down depending on weather but it'd only be to catch an extra horse so as it is it's fine for me.

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