1991 sportster electrical woes

Question

i bought my wife a harley sportster a few yrs back and it has run flawlessly until this summer. we took it out of the garage and it fired right up as usual. after about 5 or 10 min it started running very rough. i checked to make sure the gas was on (we put stabil in every yr) . after a little self diagnosis i found that the plug wire to the front cylinder was not getting any spark. after letting the bike cool for about an hour i started it up again and it ran fine......for another few min. i took it to the local shop and the recommended that i replace the coil. so after some research (and finding out that the bike had a crane hi 4 ignition put on it before we bought it) i found the right coil and put it on ........ the bike still does the same thing, the side of the coil that feeds the front cylinder isn't putting out any fire, the rear is fine. does anyone have any ideas? we have missed alot of riding, and my local shop is of no help. the next nearest shop is 200 miles away, anyone had this problem before? i was looking in the stuff that came with the bike when we bought it and there is a complete screamin eagle ignition in the box (i am assuming this is the one it came with from the factory ) if it would simplify things , i would put thisback on .. only i do not know where it goes on the bike. either way , these coils are expensive and i hate to buy another one if i don't have to . so any help some knowledgeable soul could give to get us on the road would help. thanx

Answer 1

Everyone is very quick to start replacing parts, I would take a look for some loose wires first. Like ground cables or wiring going to and from coil. Also check plug wires and connection. If you have a electrical meter, start tracing the current flow. Good luck. www.blacklistedcustoms.com  

Answer 2

I have a 2003 Sportster and I'm on my 3rd ignition, currently running an Ultima it works okay.

Answer 3

Post this in the HD section of www.badweatherbikers.com. Ask it there and in the quickboard section also. I have never seen a better group of guys when it comes to helping a fellow rider out. I also have had good luck with www.hdforums.com.

Good luck.  

Answer 4

That means the ignition it's self has gone bad,

I just went through the very same thing myself, you'll have to replace the ignition.

Crane will replace the unit for $121.00 ,that's a pretty good deal, or you can buy an Ultima or something cheap for about the same price

***** Yes , You can put the Screaming Eagle back in , right front side of the motor ( near the cam) you'll see a round ( approx. 4' dia ) cover held on buy 2 screws. The igntion is behind it.

The S E will use a stock equivalent coil, 2 teminals, rather than a single fire ( 3 terminal coil),

cranes #  [phone].

Answer 5

Your bike should have magnetic pickups, little magnets that send a signal to the ignition "black box", the same job the old points used to do.  They are usually either cylindrical or rectangular in shape.  The insulation inside of them has a habit of breaking down from heat and use.  When they first start going bad, they work fine when cold but when they heat up, they stop sending signals.  

A sure fire way to check for a bad one that works initially but poops out when hot is to take some of the compressed air for cleaning computers.  Run the bike until it quits working, remove whatever cover is over the pickups and holding the can upside down while the bike is running, aim the little tube at one of the pickups and spray.  Holding it upside down will shoot liquid, which will cool things down in a hurry.  Try one and then the other and if the problem is a bad pickup, it'll start running on that cylinder when you cool the bad one down.  However, the cooling trick doesn't work on one that's completely dead and never works.

If I were to check your bike, the pickups are the first thing I'd check.  It's amazing how many knowlegable mechanics miss that one.