Hi I just picked up my first Harley it's a 98 fatboy with a 1340cc motor it is piped and what not but it runs rough. When I put a timing gun on the rear cylinder I get a misfire every maybe 5 to 10 fires the front misfires every maybe 1 out of every 20 time it's much better but when I hit the throttle it sputters hard misses allot on the rear cylinder but will eventually pick itself back up and wind out. I'm not new to bikes or motors but Iam to Harley's do I was wondering if someone might be able to help out with a few places I should start looking. Thanks

 

Clean the carb and throw a new set of plugs in it, should straighten right out !.

 

Yup, start with the cheapest possibilities first.

 

Youve got a bad wire in the ignition pickup. The clue is that it will clear up and wind out.

 

Do the plugs and wires first then work your way back through the ignition. Also because you just got this, a compression and leak down test for a baseline wouldn't hurt. Maybe some carb cleaner in the gas along with some good high test from a station that has three hoses, one for each grade. Hope this helps

 

Wires are brand new 8.8mm. Were is the ignition pickup ?

 

Ignition pickup is in the nosecone, right side of engine. Double check to ensure the plug wires are all the way in, we get several customers a year that have a missfire problem because the wires aren't all the way in. Are you using a silicone grease on the plug wire ends. Also do you know what ignition do you have??

 

Take a good look at the pickup wires where they come out of the nose cone and follow where they route upto the coil and module.

 

There's a screamin eagle ignition control module other than that I don't know anything else off hand