stumble and dying

[shovelheadstan]

1972 FL

At my wits end. I've been dealing with this issue for years and have just dealt with it. My 72 stumbles and dies when idling. All of the ignition parts have been replaced at least twice. Spent a thousand dollars on having the head redone. Have done everything except replace the factory exhaust. Does anyone out there know if putting true duals on will solve this problem.

[vph-d]

I don't think the factory exhaust is causing your problem, try checking the carb float level to see if it set too low.
VPH-D

[T. Cotten]

Vacuum in the manifold is highest at idle, Stan!

Diagnostic #1:

http://virtualindian.org/11techleaktest.html

Testing while assembling lets you know if you over-tighten the clamps.

....Cotten

[Rubone]

True duals generally make engines harder to tune. What carb is on it? If Bendix which idle tube? Once you are sure there is not an air leak you may need to address the carburetor. Throttle shaft sealing, idle mixture seat undamaged in body, etc.

[shovelheadstan]

Had three different carbs on it. All doing the same thing. went back to a super E. couldn't ask for a better running bike while riding. have replaced the o rings several times. have bands on it now. still the same.

[Rubone]

Raise your idle speed.

[T. Cotten]

Had three different carbs on it. All doing the same thing. went back to a super E. couldn't ask for a better running bike while riding. have replaced the o rings several times. have bands on it now. still the same.

Did you ever bubble-test, Stan?

....Cotten

[Lyle Manheimer]

I had a problem with my 78 Lowrider. It had two idle speeds 1500RPM or spit and stall. After pulling what little hair I have left out and looking for carb problems that I could not find, I decided to once again revisit the ignition. The stock weights had been replaced with a set from V Twin. I found an OEM set and that solved the problem which is not exactly the same as your problem but I did note you said you had replaced all the ignition stuff twice.

[shovelheadstan]

Idle speed set at 1000. Cotton, I have not done a bubble test and don't know how but would be very interested to know. Lyle, my problem sounds exactly like yours. If I raise the idle speed problem solved but I don't think that is the right way. I know the last set of weights I purchased was from ebay. Not sure about the first set. Where can you get some quality weights. I have worked on this problem for the last 12 years or so and after so long of trying to solve the problem I give up.

[shovelheadstan]

Sorry Cotton, I forgot you sent a link for the bubble test

[joe fxs fxr]

The only reliable advance unit that you can get now is this needle bearing one (bottom of the page):

needle bearing advance unit.jpg

[T. Cotten]

Sorry Cotton, I forgot you sent a link for the bubble test

I know your pain, Stan,...

..Of going through the ignition twice (and throwing money at it), swapping out multiple O-rings, and carbs, blindly, etc...

Doing it for a living made it sting enough to just bubble-test every machine cursed enough to roll in the back door.

Amazingly, it was a successful business plan for decades, until modern times.

.....Cotten

[shovelheadstan]

Thanks everyone for the info. I will try and let you know. may be a few weeks before I get back with you. Swap meet in Clarksville this weekend.