What have I done wrong

[nicomkii]

Due to some stuck floats, leaking fuel etc I totally stripped, cleaned and put the carbs back together for the MkII. Including new gaskets, float needles, jets. Had the classic fight to get them back on struggling with the original airbag and ending rubbers.
Fired up on choke, running ok, as soon as I shut the choke off the ending dies no matter if I hold it up on a higher rev it just goes dead on me. I guess they are coming back out but what could be the cause ?

On a side note one of the biggest issues I found when cleaning the carbs was where the pin slides through the float it was very tight, a good clean sorted that but amazed me how much gunk build up from the fuel to cause that.

[Philippe]

Hi Nicomkii

did you adjust the float hight? Too low and the engine doesn't get enough fuel, too high and it gets too much fuel!
Did you adjust the air flow needles? Are the jet needles positioned in the center groove? Is the idling adjusted correctly?
Many questions I know but the main question is: what went wrong?
If you have a shop manual read the chapter on adjusting the carbs and apply it step by step.
If done correctly the engine should stay on.
Good luck!
Philippe

[nicomkii]

Float height adjusted the measurement method, but if the float height were the issue then regardless if the chokes on or off it would run out of fuel wouldn't it ? All other settings were same as before i stripped them.
The key here is it runs with full choke, but not at all with no choke.

[weaver]

applying the choke richens the mixture so it looks like you are running weak without it,are you running it with the tank on and properly plumbed in or are you using a remote fuel supply?

[Ratty]

Was it running before you stripped them, or has she sat around for a while? Symptoms are like blocked pilot jets, the drillings through the carb bodies are very fine and do block easy with crap modern fuel. Ultrasound tank is the most effective way of cleaning gummed up carbs.

[Philippe]

Hi nicomkii

use the little tube device that you can screw in the float bowls to check the float hight... new fuel has a different density , the float hight might be wrong if you used the measuring method. ( did you remove the gasket before measuring?)
The choke has a seperate chanell in the carbs to get its fuel!
Try to use compressed air to clean out the air tubes that run from between carbs 1 and 2 and from between carbs 3 and 4. If these are obstructed the air can't evacuate from the float bowls. Don't use compressed air to clean out the rubber tube from carb 3 as that one has to be attached to the fuel tap to create a vacuum to open the valve and to allow the fuel to flow into the carbs.
I think you have to search in the direction that "weaver" mentioned (running weak).
Give us an update please.
Good luck!
Philippe

[needaz1100r]

Weaver is correct. The choke circuit gets it's fuel from the same place as the other circuits in the carb, so you are not looking at low fuel at this stage.

If it runs on choke on all 4 you have fuel in all 4 float bowls, it's unlikely the level being out would cause it to cut out on the pilot circuit but allow it to run on choke.

It cuts out when you close the choke circuit and at that point you are asking it to run on the pilot circuit. The drilling in the carb body is tiny and prone to blocking. Oodles of carb cleaner through there, and not just until there is some getting through, they need to be scrupulously clean.

[z1bman]

have you compared the new needle jets with your old ones ? some of the kits available are not correct. how have you set the fuel level ? the correct way is to use a clear hose up the side of the float bowl & should be 3mm - 5mm below the float bowl mating surface. you could have sufficient fuel in the bowl to feed the choke system but not enough to supply the pilot system as this it higher up in the float bowl . try squirting some WD40 into the pilot system to see if it disperses

[Mr Bump]

Like the man says - probably to do with pilot circuits bunged up, pilot screws incorrectly adjusted, maybe if you’ve fitted new pilot screws they’re not accurately made.

One other thing - you have got fresh fuel in it haven’t you? If not change it before you do anything else.

You might not want to do it to a favourite bike to or ride it on the road now, but an ‘Italian tune up’ method is to get the bike warm, horse off down the road and rev high in second then slam the throttle shut - the high vacuum sucks through the pilot circuit and if you’re lucky clears up rough running. Does quite often work, though it sounds like something more fundamental is going on with yours.

Olly

[johny brando]

Not sure if your running OEM carbs..... but to me it sounds like there running way weak ! - Check there is not a fuel obstruction on route into the carbs . Check if there is a carb vacuum take off point that has been left open / not connected ...for say a vacuum fuel tap or maybe your manifold balance plugs are not sealing well enough = overly weak running .
Check & compare the volume of fuel in each of the float chambers ( drain & catch it & measure it via drain plugs) if theres only a tiny amount in there ! ...investigate floats - needles - seats & heights again .
Your choke fuel is delivered by a very low take off point within each of the float chambers, this could be why it may only be able to run on choke .......i.e. there may not be enough fuel getting into the carbs to service any other circuit in the carbs other than the choke circuit itself ! O yeh .....try lifting & leaving open your tank filler cap too ,as a blocked vent there will cause a vacuum & little to no fuel to run.
Cheers & happy hunting , Johny Brando.