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Carb sizes NC21 / NC24

Posted: Sat Dec 06, 2008 6:47 am
by Nickel89
Hi,

I was working on one of my VFR 400's the other and I noticed that the vacume-membranecovers of the NC21's carbs are considerably smaller than those on the NC24. I haven't had the NC21's loose yet, so I don't know what size they are. I know NC24's have 29mm carbs, but what size are NC21 carbs?

Re: Carb sizes NC21 / NC24

Posted: Sat Dec 06, 2008 7:19 pm
by Neosophist
vaccumn membrane covers?

You mean the rubbers between the carbs and the engine?

Re: Carb sizes NC21 / NC24

Posted: Sat Dec 06, 2008 8:46 pm
by Nickel89
Neosophist wrote:vaccumn membrane covers?

You mean the rubbers between the carbs and the engine?
I just noticed that the membrane covers are larger on the NC24, does this mean that the NC24(Keihin 29mm) has larger carbs than the NC21(-=??=-)?

Re: Carb sizes NC21 / NC24

Posted: Sat Dec 06, 2008 9:45 pm
by hunter
are you talking about the carb tops,(diaphragm covers) :) :) :) :)

Re: Carb sizes NC21 / NC24

Posted: Sun Dec 07, 2008 8:35 pm
by Cammo
If you're talking about the slide diaphrams then they're all the same size and fit nc21, 24, & 30.

21 and 24 carbs are very similar (same size), virtually only the jetting is diferent and some other subtle changes.

Re: Carb sizes NC21 / NC24

Posted: Thu Oct 04, 2018 8:05 pm
by decngb
I hate to be the guy dredging up 10 year old threads, but I have the same issue as Nickel89, and i *think* there is some inaccurate information in here. Since I now have an NC21 and an NC24, I have the ability to make comparisons. The other possibility is that someone put a different set of carbs in both NC24's which is certainly possible in my case since the carbs were out when I got the bike. A remote possibility is that we're dealing with the same bike - mine was apparently imported from the UK in 2013.

In any case, the diaphragm slide on my NC24 is a tad over 29mm, sliding into the carb body 30mm opening. The carb throat where it attached to the head via the rubber insulator is 32mm, and the outside measurement of the diaphragm when installed on the carb body is 72mm. All of these dimensions are larger than the NC21 carbs.

I would love to confirm these are the correct carbs for my 1987 NC24 "H" year code. According to the information I found, they should be carb ID VDE2C. I have VD stamped into the side of the carb body, but I have no idea where to find the E2C marked. Any suggestions?

Can anyone confirm or dispute the previous comment that the NC21 and NC24 should have the same size slide/diaphragm?

Re: Carb sizes NC21 / NC24

Posted: Fri Oct 05, 2018 12:24 am
by Suzuki416
I have a used set of 24's lying around somewhere... I may be able to look this weekend

Re: Carb sizes NC21 / NC24

Posted: Fri Oct 12, 2018 7:54 pm
by Suzuki416
i have the carbs beside me in a box - what do you want to know ?

Re: Carb sizes NC21 / NC24

Posted: Fri Oct 12, 2018 8:30 pm
by decngb
The outside diameter of the plastic slides would clear up everything. Mine are about 29mm. Can you also take one of the needles out and poke it though the slide from the other side? If it's like mine, it wont fit all the way into the hole because the needle is too fat. That makes me wonder what is the point of the washer shim on the needles.

Thanks!

Re: Carb sizes NC21 / NC24

Posted: Fri Oct 12, 2018 9:12 pm
by Suzuki416
ill do it in the morning - they are not the cleanest - lol