Very hot day (94 degrees) riding my 1998Sporty. Took off from light and started backfiring out of pipes. Wouldn't stay running. Pulled over checked plugs and wires and anything else. Cooled a bit and started it. Stayed running for about 1 minute and started to die and back fire. Had it towed home.

4 hours later, pulled plugs, brown in color indicated running hot. Didn't get a look at temperature gage. Started it and runs fine around block. Not at operating temperature and 10-12 degrees cooler outside.

Afraid to take to work and get stranded. Afraid to go to Harley when its running fine.

Battery 1 1/2 years old. Something getting really hot like coil? Will buy new plugs and wires just to rule them out.

Any one have any ideas?

Thanks Scott

 

Now im no mechanic but I did have a very siilar problem. Mine turned ou to be a crank positioning sensor. Good luck.

 

im hearing alot of that lately.

 

Mr hammond I emailed you bout sundays ride

 

Sounds like an ignition problem. Since it only happens when the bike is warm, I would take a hair drier or heat gun and heat the ignition pick up (cam sensor under the points cover). after you get it nice and warm, try starting the bike. If it starts and runs fine, move on to the coil, then the module. You'll know where the problem is when the bike won't start.
Good luck!

Eric

 

sounds like the bike is running rich to me. When it heats up, the air molecues expand, a bike with a rich condition will just run worse when its hot out. Less air is getting into the carb. Good way to find out, pull your air filter off the bike, run it around the block. Does it run alot better? Adjust the air/fuel mixture or check into getting a new filter or cleaning your existing one. thats my first thoughts.

 

as stated, the cam sensor is a likely possibility as well as what you thaught with the coil. I wouldn't recommend using a heat gun unless your very carefull, as you might purposly damage the components, as well as cause plastic to warp. I would try to test under riding conditions. The coil is simple to test, get a multimeter and ohm out the primpary and secondary coil, while cold they should be well within spec since the engine runs fine when cooler, if I remember the primary should be around 3ohms, and the secondary around 10kohms, so just test and remember what you got as reference. Now for the harder part, replicating the overheating. Personally I'd just buy a cheapy analog multimeter that you can take on the bike with you, then when the bike starts to crap out again, you bust out the meter and test the coils.

 

what saltlick said is also true, you said the plugs were brown, which is a sign of being a little rich, which can also cause crappy running as the bike begins to overheat. Although in my experience this ussually won't happen suddenly, but will gradually get worse and worse as the bike heats up. Electrical is more likely if it seems to have happened rather suddenly without warning.

 

I agree with you on this saltlick.....Pretty much what i was also thinkin about......Sounds almost like the bikes choke is out, which is also a RICH condition.....