Rear Cylinder not running unless Carb Intake 90% covered

cansel kansu

actually, I was fed up burning and sweating under the sunshine while working on the bike and didnt want to take the carb out and install back for each little tune on the screw. the first try was 1 turn off and I heard the back cylinder firing. so I just wrapped all and ran to the shadow... I am pretty sure that this is not the best setting but no coughs, no hassling off the idle, both cylinders firing... how happier could I be? so I just thought that I could live with how it is after annoying one cylinder idling problem.
do you, glider, think that this idle increasing can be related with this wrong setting on idle mixture adjustment?

glider

Very possibly related with a lean mixture.

You should be able to adjust the idle mixture with a short screwdriver without removing the carb. There's even a knurled thumbscrew available to replace the screw so no tools at all are needed.

EZ-Just Mixture Screw

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cansel kansu

thanks for quick replies glider.
I think you mean "EZ screw", but I dont beleive I can easily find it here. Maybe I can get it manufactured at a lathe workshop.
I was thinking to tune it with a small screw driver but when the engine was hot I didnt even give it a try.
but, my next goal is to bend a screw driver so that I can turn the screw without getting the air filter back plate out or burn my hands. or a flexible extention for a bit screwdriver kit may also be help...

cansel kansu

I didnt see the link you supplied for the screw before I posted my last message, sorry...

cansel kansu

3 days ago, I decided to dismantle the intake manifold and check the o-rings(should I call them v-ring?) sealing between the manifold and the cylinder heads. It was hard to loose the screws on the left side of the bike but somehow I managed. When I take it out, I found out that the o-rings were roasted. I was not prepared to replace them so I didnt have any correct o-rings with me. what I did was, placing 2 o-rings per side which were real "O" rings (not V shape) and thinner than original. When I tightened the manifold back, it was almost impossible to move the manifold any more, which convinced me of proper sealing. installed the carb back, did the idle mixture adjustment and put everything back on the bike.
back cylinder was not missing any more. engine was easily starting when cold, no idle increasing after warming up, the well known harley idle sound was back, smooth throttle and so on...
From the begining, I guess this was the main cause of back cylinder missing, leakage at intake!
thank you guys for your ideas and recommends...

glider

Glad you found the problem and got it fixed.

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