I have a restored '40 Knucklehead that has some starting issues. It starts right up and runs great when cold, but is almost impossible to start when warm. It seemed to be flooding with the Linkert carb, so I converted it to an S&S Super "E", but it has the same difficulty starting when warm but doesn't smell like it's flooding now. If anyone has any ideas to fix this problem I would really appreciate it. It'd be nice to take a long ride & not have to fight to start up after getting gas. The motor is 74" and has a Quickstart 2000 electronic ignition. Thanks for any help.

 

you left out info that may help

1 this is my first kicker bike
2 i have owned the bike ??? years and this just happened
3 it worked fine till i installed the elect ignition ????
4 some back round info is very helpfull -- what else did you replace the cam / 3 inch belt drive -

 

This isn't my 1st kicker, but is the 1st big twin kicker. I bought the bike as a basket and restored it, the engine was built by a reputable vintage rebuilder. It has a stock cam and a chain primary. The only alterations to the engine are the 74" flywheels, elec. ignition (which has been on it since shortly after the rebuild) & the S&S carb.

 

first thing i would check is the OHMs of the coil to see if it matches the electronic unit you have - as the coil might be over heating causing a low spark condition when hot, check the directions or call the company and see what they say about the coil -

points has always been 5.something OHMs could be 5.1 all the way to 5.9 depends on outside air temp

newer electronic ignition is 3.5 OHMs and twinkies have a .07 OHM coil

 

I have a 6 volt re-pop coil, but it's only measuring 1.1-1.2 ohms across the poles. Do you think the low resistance may be the issue? Also someone told me that sometimes these coils get hot & the windings expand & short themselves out, only to cool off & the windings retract & it works again. The thing that has me puzzled is that even after it heats up, it runs great until you shut it off, then it won't start again.

 

AH HA wont start after getting gas. Rode many knuckles through the years, stock and modified. As stupid as it sounds..when you stop for gas, restart your bike before 3 minutes, or wait about 20 minutes. just through my own experience it seem like sitting over 3 min. the heat from the engine gets the top end to hot to hot to start. just my own findings, but it always worked.

 

two things in above posts - heat soak has always been a thing - i dont drive a knuckel these days but my 1948 Indian chief has that issue as well and have had luck choking it when its that hot to start it i know it does not make sence but it works for me - we also have around a VLV D police with the high compression motor iron heads and cylinders and the fuel with the alky is playing real games with it as well --

also the coil is a china piece of $hit like all the rest of the china crap so anything yep anything is possable - see if you can find a real coil Yea they are pricy