Hey guys I have a 94 heritage and it starts missing a little after warming up. I checked the plugs and wasnt getting spark out of one, so changed them thinking it was a bad plug. didnt fix it, still not getting spark to the front cylinder. Changed the coil thinking it was a bad coil, now I have spark to both cylinders. took it around the block and it ran perfect. 10 mins later went to go for a ride and its missing again. it still has spark to both cylinder but only running on one. if you let it cool down and runs perfect??? Anyone know what it could be? Ive heard it could be something in the top end, or an ignition system problem. Please help, thanks!

 

Is it a nose cone ignition? Heat will damage those and they typically will drop the rear cylinder.

 

Head Gasket?

 

Yep. Look under the nosecone. See anything sticky leaking?