Float experiments - what would your bike do??

[bally123]

Both good suggestions:

Floats have been submerged - no bubbles or leaks, no fluid inside when shaken

I have checked, double checked and treble checked floats for fouling. I am sure floats are clear from both body of carb / bowl and also the brass overflow pipe.

I cannot dispute the fact that issue occurs when the float bowl is assembled, but given the positive valve operation during the water test I am more confident that the fuel shut off is probably ok. I was assuming the level is too high, but maybe not - possibly shutting off fuel / lowering the level is correcting some other fault...

It would be usefull to see a photo of the fuel level on a working bike - if anyone has one?

Thanks for suggestions guys...

 

[Leo]

Doesn't have an picture but mine (ASII) run great with the level set at the same place as your 2nd picture.
With the engine on, the level doesn't change. Look at your needle valve.

 

[bally123]

Solved....

Ok its fixed!!!

The overrich idle was not due to float level or shut off valve issues. It was because the jet block seal was leaking allowing fuel from the float chamber to get pulled in above the pilot jet.

Proved by holding carb upside down and filling with fuel, the fuel dribbles from the pilot jet confirming the leak. I then used an air line to really demonstrate the leak. The gasket (O ring) is not available in the UK so I managed to fix it by easing the jet block towards the leak area and re tightening the screws.
(Sudco are out of stock of these till June, but hope to get a new one fitted as the long term fix)

Photo's attached and video here:

http://youtu.be/Q3cyFuemAXQ

So shutting off fuel was lowering level to below the leak point, at which point the over-rich went to over-lean - idle instantly rose and bike then bogged when throttle snapped open.

Right now on a 40 pilot (AS 2 turns) with the DDL needle, idle is great!! - looking forward to getting on to jetting this properly now

Hope it helps someone - thanks to you all for your suggestions and help.

Andy

 

[gg3]

Thanks Andy,I will check mine in the weekend.Just had 2 days riding in slippery muddy conditions.First day put it on the stand,turned on the fuel & it leaked out the overflow?Gave the carb a few thumps & it stopped.I have checked & set the float level twice.Started fine,smoked like a diesel & green pine fire.Was barely idling so opened up the air screw 1 turn & screwed the idle in a little.Bike ran great but still a little rich just off idle.After about 15km it was idling too high.Something is up with the float height .The plug colour is excellent.I would be surprised if we had the same problem as I only have about 140hrs on the bike & it is an AS2 carb.But will definetly check it.

 

[bally123]

When you say it idled too high after 15Kms what is too high? Did the revs hang and slowly settle to an idle, or did it settle quickly just high? The fact you adjusted air screw 1 turn and got a response shows the pilot circuit is probably working.

I ran mine with the fuel tap turned off yesterday (not intentional ), it ran fine right up until it bogged and died - so my bike is now pretty tolerant of fuel level changes. Sounds like yours has similar sensitivity issues

Have you hooked up a pipe to see what the level is doing? You could try that and control the fuel height yourself - see if it behaves more consistently.

Good luck..