NC30 Carb Mod Help!

[The Hamster]

just a quick question...

In the HRC Manual it says that drilling out the vacuum holes in the slides to 2.5mm it will help throttle response a little bit. When doing this, and no other mods, will you notice any increase in Idle Speed, even if your Idle Adjuster is fully retracted?

Also, Will turning the Air Bleed screws in/out to much affect the Idle Speed?


Just a rough answer will do, not in the final stages of it yet, but my bike was running poorly all weekend so I have dismantled the Carbs and thoroughly cleaned them up. Now, when re-fitting them, the Throttle seems to jam fully on when pulled right back and the Idle speed is quite high and I cannot adjust it lower?


I am suspecting the spring on the throttle side of the carbs has lost some of its tension or has become dislodged in anyway which may cause this problem, but like I said, Im not in the final stages yet, ive simply trial fitted them and found the problems.
Also need to find where the fuel leak is...grrrr.

Much appreciated people...



The Hamster

[NC35]

Before anything I'd suggest you check to make sure the throttle cable routing has not become compromised in some way when refitting. I've found in the past the cables are easy to pinch, resulting in stuck open throttles, high idle speeds, etc.

Drilling the slides will not have an effect on idle speed, but I'm not sure about the air bleed screws - perhaps? I'd be surprised.

[superlite]

The pilot screw will change the idle, but only minorly and you'll be able to set it where you want it with the idle adjustor. If you change to big pilot jets, then you'll know about it!

[Martin]

just a quick question...

In the HRC Manual it says that drilling out the vacuum holes in the slides to 2.5mm it will help throttle response a little bit. When doing this, and no other mods, will you notice any increase in Idle Speed, even if your Idle Adjuster is fully retracted?

No

Also, Will turning the Air Bleed screws in/out to much affect the Idle Speed?

It will affect it but not a dramatic amount, the most noticeable difference is that if yopu change it too much from standard if you're still using an airbox and filter the bike will run like crap.

Just a rough answer will do, not in the final stages of it yet, but my bike was running poorly all weekend so I have dismantled the Carbs and thoroughly cleaned them up. Now, when re-fitting them, the Throttle seems to jam fully on when pulled right back and the Idle speed is quite high and I cannot adjust it lower?


I am suspecting the spring on the throttle side of the carbs has lost some of its tension or has become dislodged in anyway which may cause this problem, but like I said, Im not in the final stages yet, ive simply trial fitted them and found the problems.
Also need to find where the fuel leak is...grrrr.

Much appreciated people...



The Hamster

[The Hamster]

Thankyou people.

Martin... I am running it completely standard as I have been doing for the last 8 months, except now of course I have done the 2.5mm Vacuum Mod. I think before the Air bleed screws might of been out of sync, I put them all back to 2.5 turns out and then obviously im getting this Idle Problem.

Took the carbs off again now, put the bleed screws back in by quarter of a turn to try that and am struggling like hell now to re-fit them and test it out. (Have put new Inlet rubbers and Clips on and they are pretty soft in this lovely weather.)


The Hamster

[Neosophist]

Thats too much for the NC30.. I think it's 1 1/4 turn out?

[Martin]

Thats too much for the NC30.. I think it's 1 1/4 turn out?

No it's not, 2 1/4 - 2 1/2 should be fine. The choke isn't partially stuck on is it? It's either going to be that or as previously suggested incorrectly routed throttle cable or your throttle cables aren't adjusted properly so there is no freeplay.

[Matchlessman]

Soft rubbers should help with fitting the carbs.

When you say you are trial fitting them, you are doing everything up tightly arent you? It could be that the clips that hold the rubbers on arent done up tight enough.

[The Hamster]

Ok, problem partially sorted...

The Carbs are fully fitted and the bike runs ok, revs ok etc etc, except....


It's Idling at 5500rpm!!

Help!

I have checked the choke operation.... all seems fine and working well.
I have checked the throttle operation..... All seems fine and working.
Have checked the Idle Screw Adjuster..... all seems fine and working.
Have checked the Throttle cabling routing and operation.... all seems fine and working?


Only other thing I can possibly put it down to is the air bleed screws are too far out still. They are currently set to 2 and a quarter turns out, and I have been told on many occasions that that is fine and you shouldnt need to go any lower than that?


I am going to yet again, for the third day running, remove the carbs and check everything and I will turn the Air Bleed screws in to 1 and three quarters turned out and see if that makes any difference.


Any other suggestions, particularly easy suggestion very very welcome.



Thanks,


The Hamster

[Cammo]

It's Idling at 5500rpm!!

Pretty sure that'll be because your carbs aren't seated properly.

Use a torch and check that all the rubbers are nearly butting up neatly against the carbs.