NC24/30 carbs on an NC21?

Chrissy_J · Post by **Chrissy_J** » Sat Oct 30, 2010 11:04 pm

Quick question, guys and girls:

Can I fit carbs from an NC24 or an NC30 onto an NC21 motor, hassle free?

I have to ask because I've buggered the carbs on my NC21-ZG (I broke the throttle pulley wheel, don't ask how!) and it depends on what carbs I can get for a good price...

Thanks for the help!

Chrissy_J · Post by **Chrissy_J** » Sun Oct 31, 2010 12:12 am

Mmm... that's a long way to go, a long way to post, as well!

Post by **Neosophist** » Sun Oct 31, 2010 9:56 am

Fit, yes easy enough.

Although the carb rubbers listed for the NC21 have different part numbers to the NC24 so you might have to swap the rubbers too... I seem to think the NC21 carbs are 30mm and the NC24/30 are 32...

There jetted different though so it'd probably take a dyno day / some tuning to get it running properly.

Chrissy_J · Post by **Chrissy_J** » Sun Oct 31, 2010 6:08 pm

Thanks for that. Yeah, my carbs are 30mm so I'd get new rubbers as well.

I need new clamps too- the old ones are RTF (rusted to f...)...

Surely though, no matter what carbs I get, if I set them up as standard (or, as per the carb guide on this here forum) it shouldn't make too much difference to the running- the motor itself's broadly the same on an NC21 as an NC30, yeah?

Post by **Neosophist** » Sun Oct 31, 2010 9:14 pm

Apart from the different firing order, crankshaft, camshafts, pistons, valve gear and compression ratio

They differences with the carbs (apart from 32mm throats) is that they all use different size jets, emulsion tubes and different sized air-circuitrs depending on which carb you go for.

Even though the end result it 60bhp across all the motors they fuel slightly differently.

Technically, It'll probably run with any carbs on there, but since your going up to a bigger throat too it's not going to run right unless you adjust (tune) it with the help of a dyno / af meter.

Cheapest and easiest option is to put NC21 carbs on there.

Don't follow the carb guide on here for NC24 carbs, you don't need to shim them OR drill the slides.

Chrissy_J · Post by **Chrissy_J** » Sun Oct 31, 2010 10:19 pm

What carbs I get, depend entirely on what's available when I have the cash to do so... I do get your point about using NC21 carbs for the easiest option but I might be heading for a Dyno sometime anyway... so if I don't get the fuelling spot-on when I install the carbs, then it'll be sorted on the Dyno.

Chrissy_J · Post by **Chrissy_J** » Wed Nov 03, 2010 4:57 pm

Job done... got some NC21 carbs from the 'Bay.
Means I get to keep the existing airbox as well.

Post by **Neosophist** » Wed Nov 03, 2010 5:01 pm

Wicked stuff :-)

Be wise to check the float heights and that the jets and emulsion tubes are in the right places... give them a general clean and blow through when you get them.

If your stuck on anything give us a shout!

Off hand the NC21 has 110's in the front, 112's in the rear and has the same emulsion tubes in all carbs..

Float heights are 6.8mm too..

Post by **superlite** » Thu Nov 04, 2010 9:24 am

Chrissy_J wrote:Job done... got some NC21 carbs from the 'Bay.
Means I get to keep the existing airbox as well.

That is a big plus! The last thing you need is to mess around with an aribox off another bike. Top marks

Chrissy_J · Post by **Chrissy_J** » Mon Nov 08, 2010 3:53 pm

My carbs have arrived, no thanks to City Link...

They don't have flat-bottomed slides, but curved-inwards ones instead. These are NC24 ones, yeah?
The airbox baseplate is the same as an NC21, and the carbs are marked VD...

NC24/30 carbs on an NC21?

NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?

Re: NC24/30 carbs on an NC21?