View Full Version : Sportster problems with Joe hunt mag

06-26-2017, 7:36 PM
So I've had problem after problem and just seem to dig my hole deeper and deeper. Just finished rebuilding and putting new rings on my sportster. It's a 97 bottom end with 04 heads and higher compression pistons (10 to 1) and screaming eagle cam 536 lift I believe. It's got a pretty much brand new lectron 38mm on it. Bought a used Joe hunt mag and put it on it. The magneto has a new coil, new plug wires from Joe hunt, and I've put new plugs as well. My problem is, when I go to crank, it will only run on the front cylinder. Occasionally depending on how I adjust the metering rod on the lectron, it will backfire just out of the rear exhaust pipe but usually isn't firing at all. I've checked to see if it's getting spark to the plug and it is. I've also check to see if it's getting spark through the plug and it is. But for some reason, when you put the plug in the head, it doesn't want to fire but the front has no problem firing what so ever. Plugs are gapped at around 20 thousands. Any help or possible suggestions on this issue would be very helpful.

06-26-2017, 7:42 PM
Sounds like it might be a timing issue. You're getting spark and fuel to both cylinders, your mag just might be a bit out of time so that the front cylinder is firing when its supposed to but the rear isn't.

06-26-2017, 10:26 PM
Sounds like Benny74 nailed it you timed it to the wrong points cam in the mag.

06-27-2017, 1:33 AM
sounds like it's been timed on the wrong points cam lobe,.... set timing mark with front cylinder on compression stroke,........then points just about to open on the narrow lobe of the two lobes when at full advance.
being a 45 degree V Twin they don't fire 180 apart so it MUST be timed this way or it will run like you say it is.....

''A Harley engine has two pistons. The difference in the Harley engine is that the crankshaft has only one pin, and both pistons connect to it. This design, combined with the V arrangement of the cylinders, means that the pistons cannot fire at even intervals. Instead of one piston firing every 360 degrees, a Harley engine goes like this:
A piston fires.
The next piston fires at 315 degrees.
There is a 405-degree gap.
A piston fires.
The next piston fires at 315 degrees.
There is a 405-degree gap.
And the cycle continues

07-08-2017, 7:32 PM
sorry guys, just saw your replies. thanks for the help! but turned out that joe hunt must have sent me a bad coil because i put the old coil back in with the timing set the same to open on the small lope and it idled good on both cylinders. Any tips for getting this thing timed in perfect though? still having issues getting it perfect but got it idling on both cylinders now at least. i believe the mag is set in to open on the small lope at the 20 degree advanced mark. only put it in at 20 degree mark instead of tdc due to a guy telling me from joe hunt to set it in at 20 degrees. Thanks for the help and any advice on dealing with this thing is much appreciated

07-09-2017, 4:04 PM
Morris makes these buzzer boxes that help you time a magneto perfectly. Couldn't be easier.
Think they run at about 60 bucks.

07-09-2017, 5:25 PM
do you just use the buzzer box to tell when the points is opening and closing? i think my buddy might have a buzzer box in his shop