dell orto sha carb initial setting?

hello folks, i pulled out that screw (no 41 in diagram below) with the spring on off my dellorto sha14 and i have no idea how far it should go back in. i cant start the engine so i cant tune the screw.its starts for less than a second.then stalls.the plug is wet. do i turn it clockwise? its confusing as in the diagram it is not a normal mixture screw that restricts a channel. it seems to act as a stop for the plate.i cant understand the function of this 2 part plate with a big spring.

thanks,

B

http://www.racecar.co.uk/dellorto/motorcyclecarburettors/sha.htm

Re: dell orto sha carb initial setting?

See Ya Moped Army /

start the screw 1 1/2 turns out then adjust idle as necessary

Re: dell orto sha carb initial setting?

Don Pflueger /

start like mopdlar said. set the bike up on its center stand, start it up, then adjust the screw til you reach the fastest idle possible without the wheel turning, or turning very slow so that you can stop it without dragging the engine speed down. i usually adjust it so that it spins slowly, but i can grab the tire with my hand and stop it.

Re: dell orto sha carb initial setting?

yes. I believe on the dellorto screwing it in is idle up and out is idle down. I prefer to have the wheel not spinning so as to prolong the clutch life.

Re: dell orto sha carb initial setting?

thanks for all your replies. i think i might have additional probs with air leaking past carb.

when the motor is turned with my finger instead of plug i can feel great compression and alternately considerable suction.if i put my finger on the carb 'spigot' (on the reed valve block where you attach carb) i feel almost no suction when motor is turned. it can just move a piece of tissue paper.

how much suction should be at the spigot?

also i pulled out reed valve. the thin metal was not fully closed. at atmosphereic pressure should the reed valve be fully shut or is it acceptable to have a little curl at the end?

many thanks

Re: dell orto sha carb initial setting?

Don Pflueger /

it should probably be shut but have a limit of .005" or less. reeds only block the air/fuel mix from being blown back into the carb. they are really a one way valve. so a very small gap shouldnt hurt anything as long as it closes tightly with very little air pressure.

Re: dell orto sha carb initial setting?

many thanks to all those who replied.the info helped me in the diagnosis and narrowing down of the multiple problems with this motor.its starting now for around 2 seconds.to start however i must previously tilt the machine in the plane of the float.

that is when i see fuel moving through the pipe into the carb. a sunk float i can understand stuck in the lower position, but a levitating float?when i cleaned carb and blowed through carb gas inlet pipe it float seemed free enough to move. i even removed the float pivot axle and cleaned it.

ever happen to you? i will try working the float up and down by hand to make it even lighter to movement.

B

Re: dell orto sha carb initial setting?

Don Pflueger /

the float may be bent up too high which would cause it to shut fuel flow off too soon. but i think these are plastic floats so i dont remember if they are adjustable or not. or it could be installed upside down.

i'm gonna have to go out in my shop and open one up to see.

Re: dell orto sha carb initial setting?

Looking For Mopeds in the Bay Area /

Hey im having the exact same problem. We peadl like crazy or bum start it to get it running and then warm it up. But it dies super bad in low RPMs. any one can help? I think im just gonna buy a new carb see how that works out!

Re: dell orto sha carb initial setting?

The common Dellorto has no adjustment for fuel/air....it has only an idle adjustment. By screwing that screw in while you look thru the throat of the carb.,you can watch the slide open slightly a crack at the bottom...........a one millimeter gap is plenty for initial idling adjustment.

If it's bogging at start-up, you could have a plugged main jet or emulsion tube.

Also,a wet plug can be a BAD spark plug. Did you replace it? don-ohio

Re: dell orto sha carb initial setting?

Do a search on "Idle jet" in this forum. The resluts you find will solve your problem.

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