My 70 shovel is a kicker only. I built it from ground up with mostly used parts. She starts easy cold then flames out from time to time when idling at a signal then she won't restart. Have replaced carb, petcock, fuel filter and fuel line, ignition, wires, spark plugs, vented gas caps, and coil. I'm not sure what the correct coil should be and suspect it may be the problem. The motor doesn't miss a beat on the road. From time to time I have recovered the flame out with a quick twist of the throttle which really confused the issue with electrical problem or fuel problem. I would appreciate any input. Thanks.

 

electronic ignition coil is 3.0 ohms >>> you did not say what you have

point ignition coil is 5.0 ohms and yes it does make a difference

do a compression test yes its kick start I read that - and a leak down test you are looking for more then 15 pounds difference OR 10 percent difference - to see you have an issue

the fact its an hot idle issue - fuel line vapor locking

intake O Rings will do that -- incorrect jetting - yes I read it runs good to you - picture the plugs and post them might help

you did not Say once it cools does if it re starts and then 15 - 20 min later it does the same thing ???????///

 

She has a Malory Pointless ignition. Is this considered an electronic ignition which requires a 3 ohm coil? I currently have a Custom Chrome RevTec Hi Performance coil which I have no idea of ohm value.
She will flame out at any temperature at an idle. Even within 3 minutes from first fire with cold engine. At that point it may take 30 or more kicks to re start. I tired easy so recently I tried pushing her and she fired up in second gear on first try.
I constantly on edge at evey stop light, which is taking the fun out of riding her.

 

get an ohm meter from harbor freight for 3 bucks and check it

have a test light handy and see if its voltage to the coil - ignition switch issue

pull the fuel line off see if it has flow when it stops

or bring a bucket of cash to a bike shop and drop it off

 

what John says..... mixture too rich???do a plug chop and post pics of the plugs

 

That Mallory should take a 5 ohm coil - the coil you are describing is most likely a 3.2 - what happens with the 3 Ohm coils with points or inductive ignitions is the dwell is too long and the coil charges too long and heats up - if it is the coil heating you should be able to feel the temperature of the coil in the HOT zone - they get HOT - however - here is what you should check - mke sure there is only 1 filter screen on the fuel line - if there is one in the petcock in the tank - do not have another in the fuel line - it will do exactly what you are experiencing - I have experienced this multiple times with multiple bikes - this may not be your problem but that symptom has pointed me to dual line filters in several cases

 

How do your plugs look? If plugs don't show a rich condition and carb is properly adjusted (idle mixture screw), try going up one size on the slow speed jet.

BTW - old carbs were not constant velocity; so you need to blip the throttle just before idle when coming to a stop.