Ive been tinkering with the 1972 xlch with bendix carb. We got the bike as a project and have worked on it trying to get it going. Im new to ironheads. The problem Im having is when the bike gets hot it wants to pop at idle and go dead. Ive put new points & condenser gapped by the book, adjusted timing with dial timing light, by the book. Replaced plugs and coil and rebuilt carburetor. Adjusted valves by the book No evidence of intake gasket leaks. Im thinking I may have to tesr back into csrb. Thought Id check here for recommendations.

 

Hey Road Captain

When it pops & goes dead - are you attempting to give it gas? Then it pops & goes dead? Just trying to understand when the pop occurs

 

It will do pop when I give it gas, but it will also pop and go dead just sitting there running. On a cold start it runs fine til hot. When I cold start it, I will screw in throttle thumb lock screw higher than idle to warm it up. If I unscrew the thumb lock (when hot)to let it come down to normal idle, it will run a few mins then pop and do dead without me touching throttle. Runs good at speed going down road, no hesitations or pops. Then I come to a stop, and if I don't keep it slightly reved, it will pop and go dead. If I idle it up to 1500-2000 rpms it won't pop or go dead. Its the Bendix with fixed jet. I pulled petcock and screen / tank are clean.

 

How far from seated is the air mixture screw?
Do you need to thread in the idle stop screw a little?
Is the idle jet clean?
Absolutely no air leaks?

 

Air mix screw is 2 rounds out. Thats where it seems best. In makes it lean and diesel when I kill it.

On idle stop, it has to be idled too high to not pop and die.

It has a fixed jet. Is it removable? Cant remember. Been a while since I had it apart.

Gotta check again for air leaks. Ive sprayed wd40 on it and no change.

 

Think I found the problem, or a problem anyway.

 

I don't use the squirter on any of My Ironheads.. Don't need it if tuned correctly...no reason to Throttle jockey..stabbing the throttle accomplishes Nothing!! and Do Not Idle so Low..
Edit to rescind the "any". There is an old Ironhead here, that is Tired, mostly Bone Stock. It needs to be quite Rich, plus a small Squirt, to act proper! So...If you try to replace that "packing" get the real one from Facet Fuel/Zenith

 

I've had a fairly clean XLCH project for a couple of years now. Had the stock Bendix ultrasonic cleaned and kitted with OEM parts; also changed o-rings and fitted a new support bracket made of angle aluminum. Runs like a top! Smooth starts and relatively smooth engine up to 75 mph. I credit the proper cleaning, rebuild and setup to a gray haired HD mechanic friend; I hand fitted the support bracket and o-rings myself.