Idles fine - then dies

[Manfred]

Ken,

My airhead is a 1987 - does it have the "bob weights" you mention?

[Ken in Oklahoma]

Ken,

My airhead is a 1987 - does it have the "bob weights" you mention?

There are indeed bob weights inside the '87 bean can, even though it has the hall effect sensor. But I was thinking of the /5, /6, and /7 pre bean can ignitions of my experience. What I don't know is if the later ignition is similarly afflicted.

In any event I would still suggest using the mixture screw for touch up purposes after setting the idle with the screw on the throttle butterfly.

Ken

[Manfred]

Thanks, Ken. I only moved the mixture screws a "notch" - as they say in the Bing book. This put them a smidgen closer to the 1/2 turn out that the Bing book recommends for my carbs. I started them at about 3/4 turn out. The main adjusting I did today was with the idle screw - whatever proper name it has

[Deleted User 62]

Thanks, Ken. I only moved the mixture screws a "notch" - as they say in the Bing book. This put them a smidgen closer to the 1/2 turn out that the Bing book recommends for my carbs. I started them at about 3/4 turn out. The main adjusting I did today was with the idle screw - whatever proper name it has

Manfred, you should build a $4 carb synchronizer to help you visualize whats happening at various throttle settings. Also, those 1/2 turn mixture settings in the Bing book are only base settings that should get the engine to run. The mixture screws (the ones in the carb) are then adjusted individually to get each cylinder to run its best, with the idle screws (on side of carb) backed off evenly to just touching. The mixture screws do not have to be the same setting, both sides. Those idle screws then get adjusted after the mixture screws, and finally the cables are adjusted, to ensure even pull. $4 carb synchronizer, with the instructions: http://www.airheads.org/content/view/183/98/

[Manfred]

Tim,

I have one of those sync tools in my garage - built it years ago when it was a $2 tool I've used it before but need to put heavier liquid in it. Right now, the old girl is running very good and I will keep it as is for a while so I can become familiar with it.

This forum is a great resource! Thanks again to all and safe - and FUN riding.

[George Ryals]

Manfred, don't put heaver fluid in your syncronizer, shove an old carb jet in each end to restrict air movement. Or buy some tiny plactic valves like come with vacuum gauge syncronizers. The restriction/valves damps the movements of the fluid. You could just twist some mechanics wire on the hoses to pinch it almost shut. If you forget and blip the throttle you won't suck the fluid into the engine, either.

[Manfred]

Thanks for that reminder, George. I had meant to put them tiny valves in there but never got around to it. I do have some wire that would like to volunteer for the job

[SteveD]

I've used a couple of artery forceps to crimp the hose. Works a treat.

[Ridercam]

I recently went through a similar carb issues as I chased down the problems. after I rebuilt my carbs, the problem continued. I played with the coils. I changed the wires. I did three tests on the can....
It turns our that since I hadn't retorqued the heads since I put new pushrod seals in 4000 miles ago, once the bike warmed up the idle died because of the slop. Boy, did I feel foolish not looking at the entire problem and becoming focused on singular perceived problems. a lesson yes - mark the fixes, go back and do the follow up after the recommended time. the upside, the bike rides better than it ever has.

[Manfred]

I read somewhere about using mid-grade gas, due to compression ratio of these bikes. I filled up with 89 octane for the first time and WOW! what a difference! No pinging at low rpms, smoother starts and better power. The old girl is running GREAT!