NC30 carby jetting - DIY guide

[CMSMJ1]

Leave it in...that is the mystical rubber flap...take it out and the bike doesn't like it. You could always try it and back to back test it..I'll put 50p on it working worse without it

[pauliealdridge69]

No, lol. This isn't the mystical ford Capri mud flap that cut to fit by a Honda technician 20 years ago. This is the side of an old dust pan, drilled and popped with someones false teeth by the looks of it! White plastic, both the Honda flaps are in place but I can see no reason for this flap unless someone was trying to reduce the air flow... Would that richen it up? It fills the hole up blocking the snorkel nearly right off????? Some monkey or genuine reason?

[skinnydog0_0]

Could possibly be a bodg job at the HRC snorkle?

[porndoguk]

WOW, just had a look at some carbs for a friend whos just bought an NC30, 1989 F Reg Grey import,

and what can i say!

filthy carbs in side and out,
most of the screws had been rounded off, or replaced with sloted screws, so was a good indication that someone had allready been in and they were not virgins.

120 jets all round,

i replaced them to 115 front 118 rear
emulsion tubes as always were the wrong way round, 5 holes front 4 holes rear, now swaped around
the needles had 3 x 0.5mm washers so had raised them to 1.5mm ive removed one washer on each needle.
the slide had NOT been drilled but i drilled that out to 2.5mm

the carbs look way out of ballance 2 of the 4 butterfly valves are slightly open on either cylinders 1 & 3.

the float bowls look like a sand stone quarry with shit loads of orange silt, and dirt everywhere,
i havent checked the floats but they probally arent right.

also the slides had aload of dust and dirt in the chambers which were scrapping.

now the float valves i removed the floats and valves, and then undid the 10mm nut to reveal no filter now the last 2 sets of nc30 carbs ive had, had filters on the bottom of the 10mm float valve? is this model specific or have they been removed?

so now i need to get the externally cleaned before i start on the inside.

[Cammo]

now the float valves i removed the floats and valves, and then undid the 10mm nut to reveal no filter now the last 2 sets of nc30 carbs ive had, had filters on the bottom of the 10mm float valve? is this model specific or have they been removed?

All of the carbs I've seen have had them, pretty sure they'd all be the same.

[superlite]

This is the side of an old dust pan, drilled and popped with someones false teeth by the looks of it! White plastic, both the Honda flaps are in place but I can see no reason for this flap unless someone was trying to reduce the air flow... Would that richen it up? It fills the hole up blocking the snorkel nearly right off????? Some monkey or genuine reason?

It's not an HRC airtray is it? The originals are made from thin white plastic. Not sure why anyone would bother fitting it with an airbox though?

[porndoguk]

now the float valves i removed the floats and valves, and then undid the 10mm nut to reveal no filter now the last 2 sets of nc30 carbs ive had, had filters on the bottom of the 10mm float valve? is this model specific or have they been removed?

All of the carbs I've seen have had them, pretty sure they'd all be the same.

thanks for confirming that cammo, i had a feeling they were missing these carbs have been fettled badly,
and wayne said the bike was runnin crap so i said ill sort them out, didnt realise the take i was taking on.

i need to see if i can try find him the filters, as DSS want £24+Vat each and he needs 4!

[Smev]

I'm in the process of fettling my RVF carbs.

I discovered alsorts of anomolies with mine, which I have so far rectified.

I am just a little puzzled tho. I found two 0.5mm washers under each needle. I'm sure there should only be one.

I know Cam has said several times through the thread that HRC springs are the way to go!

I think this must be someones attempt at tuning the carbs/geting rid of flatspots.

My question is - should there only be one washer as standard? And should I take them out?

[Drunkn Munky]

Smev, I can see why you confussed mate it's a bit of a grey area this as i dont think there's any rock solid Info on here regarding it but with RVF carbs I'm sure the HRC slide springs do the same job as a extra washer under the needles so you should stick with 0.5mm washer, DONT drill the slides and fit HRC slide springs.

That's how I understand it anyhow,

[CMSMJ1]

I have 1 washer and HRC springs.

they are not related.

The washer richens up the curve as the needle taper is further out of the jet before the slide starts to life. as the taper is pulled out the jet by the slide lifting then with more wahsers this effectively happens sooner and so richening up that part of the curve,

The HRC springs allow the slide to react faster to the vaccum ont he back of it and so the carb will hit full open throttle faster. Of course, you don't want to be having the slide lift that fast if the needle is going to be running too rich and the bike won't take the fuel....


that make sense?