NC30 Carb Mod Help!

[Cammo]

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?

They are fine and you shouldn't! Your problems are elsewhere.

[The Hamster]

Thanks stickshift, but I have also checked the Carb seating and they appear fine. Two of us and sheer brute force got them on and as far on as possible and they do all appear to be seated properly. I thought this was what was causing the problem when i first rebuilt it, but I cant see how it would be the problem now?


Really boiling my piss this is, and Honestly, Ive concidered getting rid of it this evening and getting myself an nice and simply, newer inline 4. Might also sell up my project bike to fund this too as I really can not be arsed to go through all of this hassle again!!!!!!!!!!!!!



PLEASE HELP, Im begging you!!!!!!!!!!!


LOL



Me ----> <----- My Bike.

[The Hamster]

This is really boiling my piss now...


As far as I can see..... EVERYTHING is exactly right. (obviously something isnt but I cant see what?)
Yet, Im still having these symptoms:

The bike runs ok, but when you rev it up it is very slow to return down the rev range. It will rev up nice and quickly, noticeably quicker with the 2.5mm Vacuum hole mod, but it comes down the range very slowly. On the road this will probably be fine through the gears, but I dont want to have this problem when in nuetral or when on my drive for instance. I want it to be just right!!


I have put the Air Bleed screws completely in. They are fully closed and the bike is now Idling at just over 3000rpm, so it is coming down at least!!!! But its still not right.

This obviously points to an air leak somwhere, but to hell if I cant find it!!!! And the carbs are seated correctly?


So please, if anybody can help, It will be much appreciated!!! VERY MUCH! I need this bike back to perfect working order by monday!!!!!



The Hamster

[CMSMJ1]

get checking for the air leak then...spray ome carb cleaner at the rubbers, one at a time...if the revs pick up you found it..

I'd also look about putting some std slides back in - it may be that you have drilled them and it doesn't like it.

Not all bikes do like it..

How is the rest of your setup - you running an airbox while doing tihs testing or is the bike part stripped still?

Have you balanced the carbs?

Sod the IL4 vibe..get this bad boy sorted

[The Hamster]

I think, fingers crossed here, and I mean really crossed and touching the biggest plank of wood you could ever find...


Ive sorted it. Kinda.


The bike is now Idling fine at roughly 1400rpm as normal. I removed the carbs again, checked the linkages again and it seemed that the butterflies on the Main throttle Carburettor was slightly open, even when the throttle is fully closed. ths was because the screw that connects the throttle linkages on cylinders 1 and 3 was too tight causing it to apply too much pressure on the linkage and opening the butterfly slightly. A quick tweak and they are now working good again.


however, i am still getting the problem with the revs returning slowly, although it has improved. the throtlle seems to stick a little bit as far as I can tell, and this time it definetley is NOT the carbs at fault. and the cabling looks fine and free?. Also, when the throttle is pulled back the bike struggles to pick up, but it does so eventually. its as if its choking. I take it this could be that the Air bleed screws are too far out then? (Currently at 2.5 turns out!)


So, some more fettling and I think i will get there. Thank god. I need to be 45miles away on tuesday!!!

[Matchlessman]

The throttle sticking could be because the throttle cables are too tight.


The revs dropping too slowly could either be an airleak, or that because youve drilled the slide holes out, youve changed the rising and falling rate of the slides. - My CV carb theory is a bit vague so apologies if this is waffle but im pretty sure there is a relationship between airflow onto the slide and the rate that it moves. If youve changed the rate that it moves, you are going to be changing where the needle is in relation to the amount of air going into the engine.

Did you change the springs along with drilling the slides?

If i were you, i would put the standard slides back in and hope that someone thats played with carbs a fair bit and seen what does what can explain whats happening with yours.