200 Elite with a cough.

[hardemon]

I am working on a 1961 200 Elite that will not continue to idle. The bike starts up OK but will not keep running on idle. It coughs through the carb, UB 24, then stalls. Starts up alright,runs for less than one minuite, then coughs and stalls again. I have checked the tune up and valve and everything is within spec. I have substatuted the coil, condensor, and plug wire, no help. I have cleaned the carb within an inch of it's life, i have an ultrasonic tank. Idle jet clear, all the passages are clear. I changed the needle setting, no help. I am out of ideas. HELP.

[Rick]

Sounds like you've been thorough, but just in case, have you checked the tank fuel valves(petcocks) and the vent hole in the gas cap? The fuel tank vent got me once- drove me crazy for a while, but was an easy fix.
Rick

[hardemon]

Thanks Rick for the thought. I have even used another tank with fresh fuel and no cap, no help. Just tried an Amal carb, still coughing and stalling.

[tony.s]

I think that your fuel-tap (petcock) might be restricting the flow into the float, you could do a flow test of the tap, it needs to flow about 1 pint pr. minuite ,this is not a precise ammount,but the time is.
Try running the engine with the dellorto & when it is about to stall, press the flooding plunger on the float-chamber to bring more fuel into the carb. & see if that makes any difference to the running of the engine, if it makes it run better then the carb. is lean on the pilot jet, so go up one size & try again.
the slide could be lean, try one with a lower cutaway.
If all this fails to get a good running engine, then the carb. is worn-out on the body where the slide runs up & down. it is drawing air past the slide & ruining the low settings.
I hope I havenot brought you all bad news, but keep at it & sucess is just around the corner.

[wcorey]

And the motor runs ok other than this one issue...?
Sticking valve?



Bill

[hardemon]

At this point I have not ridden the bike. I am working on it for a friend to compete in a Moto Giro, so he needs to be able to ride at slow speeds. I will try the fuel flow test, I am starting to think the carb is worn out. How much slop is allowed in the carb body? I don't hear any chatter like on a worn out Amal. Thanks for the ideas, keep them coming. I worked all day today and got nowhere. Sticking valve? How would I tell if one is sticking. I know this bike sat for an extended period but not exactly how long.

[Bevel bob]

Does the bike sit straight on the stand or loll over to the kickstart side?, try raising the fuel level by twisting the carb on the stub.

[hardemon]

Thanks Bob. I have used an Amal 930 carb instead of the Dellorto and have had the same results. I am thinking at this point it might be a sticking valve. I have fogged the intake with Marvel Mystery Oil and it has been sitting for four days. I will start the bike tomorrow and take it and run the crap out of it. Hope this dose the trick. If not I think a head tear down is in order.

[Bevel bob]

Its possible that the ignition may be advanced or that the AAU is weak and allowing the advance to jump which is stalling the motor at slow speed.Dirty plug also a possible ,too rich at tickover?.