Hey guys, this is my first post so be gentle please! I have trawled the web for a conclusive answer but without result so here goes. I have a 1997 Heritage and have developed an annoying problem. The bike starts fine everytime and ticks over without any issues. I can pull away fine, but when I get about 200M down the road it starts missing on one cylinder. First I completely lose it but then over a period of about 5KM it slowly comes back. After about 6-7KM it runs fine for the rest of the day. Im not over familiar with engines and so have gone through some basics. I have cleaned and set the plugs, and have just changed the coil and HT leads as these seemed to be my main suspects, as they were both old and corroded, all with no result. My next step (though probably should have been the first) is a set of new plugs. I have tried logic which is probably flawed! I figured that it can only be fuel or electrics. If it were fuel then it should effect both cylinders as I only have one carb, so it must be electrics??

         I have little knowledge on Harley Engines but am willing to learn. I know I will regret this but ....if I am being a dumbass let me know and lay some knowledge on me, I am a keen student

DO you have the HD OEM electronic ignition or an aftermarket. If aftermarket which one? Sounds like a bad plug, but weird that the cylinder comes back after the bike warms up, as usually if it's coil or ignition related it starts failing after it warms up.

How did the plugs look by the way? I think an oil fouled plug would cause rough running until it heated up a bit but have never had to see for myself.

You could check the wire leads from the electronic ignition to the coil to see if a wire was pinched or corroded at a terminal.

There are some very good techs here with more knowledge than I so maybe when you come back with more info they will assist.

Mate, how long do u use the enricher for when u start it?

well good news guys. I put one new plug in (due to the fact that the shop gave me two different ones !!) and struck lucky. The bike runs fine now and I got my HOG smile back. I guess my first hog maintenance lesson is change the cheap bits first!!, still I needed new HT leads as they were bad, and Ive put the old coil on e bay. Many thanks to all you guys that posted advice so quickly, its much appreciated. Hopefully I'll be able to return the favour one day. :0)

 Hi ,

Harley Spark Plug Cross-reference		EVO 1340 (80 CID)
H-D Standard		5R6A
H-D Gold		5R6AG
H-D Platinum		5R6APP
Screamin' Eagle		EVS13S
Bosch / Platinum		WR8DP
Champion		RN12YC
NGK		BPR5ES-11
NGK Platinum		BPR5EVX-11

I run the NGK's on my 89 Heritage and have had no problems with them.

Used to run the same plugs on my Old Shovel.

Cheers,

Cris..

hello,  dont suppose you know what plug to put into a 1200 - 06 sporty?

Glad to hear ya got it sorted lanceinoz. ALWAYS do the easy (and usually cheaper) stuff first.

Been running the NGK "plain" BPR5ES-11 plug in the Evo since 2005. Bought a bag full of them at Supercheap for a little over $2 each as Kiwidave mentioned...

 

Plug Manufacturer Sportster 86-up Evolution Engine Plug Gap .040" H-D Standard 6R12 H-D Gold 6R12G H-D Platinum 6R12PP Champion RA8HC Screamin Eagle EX12S EX12P NGK DCPR7E