NC23 bizarre fuel consumption

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BillingCBR
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Bike owned: '88 NC23, NC30, '98 R1, NC35

NC23 bizarre fuel consumption

Post by BillingCBR » Sat Jan 15, 2011 11:21 pm

Hey guys got a bit of a bizarre thing going on with my NC23 Triarm that I hope one of you can explain.

Up until just before christmas I has Motad stainless pipes with a straight through end can, with 110 Keihin jets and on a tank (from full to reserve) I could just about get 90 miles before reserve most of the time, mostly riding sensibly with the odd flick of the wrist to overtake someone etc.

I fitted the Dic alu system and rejetted to 110 Dynojets as recommended by Graeme France, and not only have I noticed that the bike is a bit pokier (bit dead under 4k, ballistic much over 9k) but it's better on fuel, I've got 109 miles so far without hitting reserve, I had to check I hadn't left it on reserve last time I was so surprised! If I've worked it out thats a bit over a 22% increase for increasing the fuel flow, and also, seeing as it's new and loud I've been riding like a bit of a tit where it's possible, with lots of high revs and wide open throttle :|

Anyone got a good reason for this?
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire

angry_rob
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Re: NC23 bizarre fuel consumption

Post by angry_rob » Sun Jan 16, 2011 10:14 pm

I'm not the most knowledgeable person about these things and I can't really explain why your fuel consumption has gotten better (I assume Dynojets are more efficient and that your new exhaust system is more efficient and lighter as well as having better jetting than before could increase your MPG), but I was just wondering what gearing you have, as with my NC23 Tri-arm I get about 150 miles until reserve on standard gearing, I do drive a bit like a granny though.

Wozza
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Re: NC23 bizarre fuel consumption

Post by Wozza » Sun Jan 16, 2011 11:01 pm

90 miles to reserve does sound a bit low. Have you changed anything else like pilot screw setting?

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BillingCBR
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Re: NC23 bizarre fuel consumption

Post by BillingCBR » Sun Jan 16, 2011 11:23 pm

everything else is standard afaik (35 pilot jets from memory) don't know whether I maybe dislodged some dirt from under a sticky float or something? The bike is used for short journeys to work, and gearing is standard, had it up to a little over 140 (got a mph converter) on the Abba stand.
'89 CBR400RRJ and '91 VFR400R NC30 project
Neosophist - The NC30 doesn't go very well when it's on fire

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Re: NC23 bizarre fuel consumption

Post by Mikiboy » Sun Feb 06, 2011 7:59 pm

If its gutless, chances are the jets are out and the jetting has been done by guess work.
get it done on a dyno and you should be gettinging 130 -150 miles to a tank.
I track mine and get 70 but when it was ridden on the road i seem to remember it doing 50ish mpg when i worked it out. Mine had a full daishin ally system which is similar/same as Dic

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