Engine misses until warmed up ... Coil?

[Tuxedo7]

I have a 1940 EL (Knucklhead) The engine has started missing (as best I could tell, only one cylinder) until the engine is warmed up. It seems to also make the bike more difficult to kick start. Once the bike is warmed up, it tends to sputter at idle, or when decelerating. I have to slightly rev the engine or keep the choke on while it is warming up or else it will cut off, and I don't like having the engine run at that high a speed while at idle. I have gone through the points and plugs. All seem to be fine. Additionally, I've worked through "intake leak" test procedures, and that is not the problem.

Anyway, I have a relatively new coil on the bike (chinese repop), that I understand are not of the most dependable quality/manufacture, and am wondering if the coil could be causing symptoms like I am having. Again, more difficult to start, missing while idling/warming up after start, and for a while after beginning a ride. Once it's nice and warm, she runs very well.

Would the coil perform differently when the engine is warm ... I'm not sure that would make sense, but am wanting to consider all potential issues. Suggestions/recommendations?

Thanks.

[junior]

as a rule, coils usually give problems when they get hot. i assume that you still have the stock linkert carb on there and i am not familiar with them at all. however, generally, even though you've looked at an intake leak i would look into that possibility again. also- readjust the idle/pilot mix. engines require more fuel when cold (hence the choke) and if it is ok when warm, then i'd think something was causing excessive lean condition when cold.

for grins though- take a look at the points.

j

[Tuxedo7]

as a rule, coils usually give problems when they get hot. i assume that you still have the stock linkert carb on there and i am not familiar with them at all. however, generally, even though you've looked at an intake leak i would look into that possibility again. also- readjust the idle/pilot mix. engines require more fuel when cold (hence the choke) and if it is ok when warm, then i'd think something was causing excessive lean condition when cold.

for grins though- take a look at the points.

j

Thanks for the input, Junior. The points are good, but I am with you on thinking that I may need to do more hunting for intake leaks. Also, appreciate your suggestions on on the idle mix. By the way, I have an S&S Shorty on the bike, and am seriously thinking about replacing the old Linkert once I get it back in order. It ran well before with an M74. I have a correct M25 that I need to pull together and go through.

Thanks,
Vic