NC30 carby jetting - DIY guide

[trademe900]

Please, can anyone tell me how to get the needles out of the diaphragm on the NC35... I don't understand the guide when it says, use your phillips screwdriver to unscrew the needle retainer. I have looked as hard as I can down that tiny hole in the middle and can not see a screw. It's truly doing my head in.

[CMSMJ1]

stick a screwdriver in there and turn..it comes out on half a turn IIRC

[trademe900]

In case anyone has the same frustration again... to clarify- with the NC35 needles you have to push down hard on the tip and it will pop out the back of the diaphragm. There is no screw down there. Just seems a little dodgy because the needles are probably quite delicate.

[CMSMJ1]

What he said...ignore me, I was talking bollocks!

[Cammo]

I don't understand the guide when it says, use your phillips screwdriver to unscrew the needle retainer. I have looked as hard as I can down that tiny hole in the middle and can not see a screw. It's truly doing my head in.

Apologies, that is for nc30 carbs only.

Glad you got them out in the end, the haynes manual explains the procedure for rvf carbs...

[Zaz]

Great guide, i will be following it when i set about rebuilding my carbs, however, a couple of questions forst:

I have a 1989 'k' import nc30 with a Viper endcan, the bike has done 4500 miles in 10 years, had a restrictor kit fitted for the last year (400 odd miles use previous owner) and is suffering a bit with stalling, high idling, power delay etc. Runs smooth when on a run, though it did die on me last week.

Anyhoo, i have all new OE clutch parts on the way, clutch and choke cables too, so i thought while im at it i will do the carbs too.

So, i am compiling a list of parts i will then buy, so far i have:

main jets 118f/120r
float chamber gaskets
probably emulsion tubes
probably needles
0.5m washers
probably OE throttle cables

Questions are, what other bit are recommended while i have it opened up, what o-rings will i need and for where, price wise what is my best option for sourcing parts and to save trawling all 15 pages (evil eye off mrs for being online again) what part numbers am i looking at ?

Thanks for your time :)

[lukemillar]

Ran through this on my 89 nc30 today and just wanted to add a big thanks to Cammo. Went super smoothly and highlighted a load of issues from previous owners tinkering!

The only thing I noticed was where the 2 front carbs join, there is a pipe (possibly a T joint?) and 2 rubber grommet/washers. Same on the rear carbs. Both of these grommets had split all the way through so they were really loose. I even found a bit of insulting tape half stuck to one like someone had attempted to bodge it!

Should I be worried and looking to replace these?

Cheers
Luke

[Cammo]

Glad it all went smoothly Luke, it's pretty common to find a previous owner's mistakes lurking somewhere in there.

Should I be worried and looking to replace these?

Those plastic rings just help to seal the pipes from air leaks. The pipes are for the air intake/exhaust from the movement of the carb slides. They run to the sub-air filter at the back of the airbox base which filters the air.

It's no big deal if air leaks are present in my opinion. Some will say that unfiltered air is no good for the slides, but in reality the sub-air filter material isn't terribly effective at removing small particles anyway.

[lukemillar]

Glad it all went smoothly Luke, it's pretty common to find a previous owner's mistakes lurking somewhere in there.

Thank Cammo - Cool, I won't worry about it then!

[Man_Named_Dave]

Cammo,

I've recently been feeling that the bike's been pulling a little less than optimally, ie not as smooth as I would like. The 33bhp washers would be the most obvious contributor, along with an old vacuum hose (should be addressed as I fitted a Rick-O one yesterday).

Is there a possibility that the reduced air intake would necessitate an adjustment to the pilot screw settings, which are currently set as per your guide? Bearing in mind that I'm running either 110/112s all round.