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Nc23 standard carb jets and settings...

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spritz46

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Nc23 standard carb jets and settings...

PostWed Aug 09, 2017 2:51 pm

Hi all,

Would someone be able to point me in the direction of the standard list of jets/screws on a base set up NC23. It's a 98 RRJ if that helps. Oh and it's standard exhaust and air box. Just looking for the details on factory set up to get my starting point.

Looking for sizes and settings of pilot screws etc as have no manual and the carbs were in bits with bits missing on collecting the bike.


Thanks in advance for any help.


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spritz46

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Re: Nc23 standard carb jets and settings...

PostWed Aug 09, 2017 7:00 pm

So bit of further digging...


Main are 115
Pilot 40
2 1/2 turns out for pilot adjusting needles

Im going to need a set of carb float needles and have some others to hand but the screw in seats which the needle float goes into is stamped 2.4 rather than the original 2.0 stamped ones, the needles won't go in the 2.0 seats but does anyone know if swapping the seat and float needle to these will work?

Also what other settings do I need to be aware of? apart from the pilot adjusting screw at the edge of each float bowl cover being 2 1/2 turns out are there any other listed 'turn specific' parts to do when reassembling?

Thanks again to anyone who may throw some advice my way.
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spritz46

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Re: Nc23 standard carb jets and settings...

PostWed Aug 09, 2017 11:44 pm

Ok so some further late evening pondering...

The float needle and seats seem to only be as either a whole refurb kit or just the needles available.

So the needle and seat is to let the fuel through to the bowl. This then shuts off when the float presses on the needle and seals it effectively shutting off fuel until the float has lowered enough to reinstate the whole cycle again. So, logic in my mind says 2.0 seats to 2.4 seats won't make any difference as long as the seat and needle match. The fact it let's more fuel through will be countered by the float rising quicker and therefore shutting it off at same flow rate albeit a quicker refill time...

Any one want to chime in here??




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CB1pod70

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Re: Nc23 standard carb jets and settings...

PostFri Aug 11, 2017 3:28 pm

Your settings are all as per the manual so nothing more to add here other than don't forget to check your float heights (7mm). Not entirely sure what the difference will be between 2.0 & 2.4 seats are but I suspect is to do with increased fuel flow. as long you're using the correct needles with the seats, then your logic makes sense. The needles may be longer than standard so this might require some adjustment to the metal tab on the floats to get the right float height.

Someone on here had a cbr400 Haynes manual for sale recently or if you do a bit of googling there are often PDF versions of the manual available online
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spritz46

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Re: Nc23 standard carb jets and settings...

PostFri Aug 11, 2017 9:39 pm

Thanks again CB1pod70


Needed the float height so thanks for that. Just in case this ever comes up again I spoke with Allens performance in Notts who were fantastic help explaining a few things. The 2.0 - 2.4 sizing will be fuel pump dependent pretty much. Despite the logic being there about matches size of needles and seat, the lower number suits a higher pressure application. The 2.4's would be more of a non pump or gravity fed set up.

I'd be interested to find out from anyone not running the fuel pump for whatever reason to whether they have used 2.4's or larger.

For getting my base project setting achieved I'll be keeping the pump and so will need to find the needles for the 2.0mm seats.

Hope that helps anyone else and thanks for the info again CB1pod70, legend.


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CB1pod70

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Re: Nc23 standard carb jets and settings...

PostMon Aug 14, 2017 9:33 am

I think I've got a full set of seats & needles from a dismantled set of carbs if you need them. I'll check & let you know.

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