View Full Version : HELP!!! '73 Only firing on one cyclinder


73hdsporty
05-07-2008, 09:41 PM
hey guys i got a prob and i want to see what you guys think. my bike set all winter and when i fired it up here a couple of days ago it stared with no prob it was running a little rough but i figured it was old gas, then on the way to the gas station it started to miss so on the way home i stopped and got some new plugs. got it home and parked it, the next day i stared it and it was only firing on the rear cylinder so i figured it was a fouled plug so i put in the new ones in and it still fired on just the rear cylinder. ive switch plugs, plug wires, check compression and got 90 pounds on both cylinders both plugs are firing good n blue, however not at the same time its one right after the other and i thought both plugs fired at the same time but only one cylinder fired and the other was wasted on the exhaust but i might be wrong on that. the ignition is a Spyke super comp single/duel and and the coil is the Spyke Igntion coil with three therminals and two spark plug connections. im starting to think my ignition is bad but im not sure and i would hate to spend the 300.00 for a new Crane HI4 and it be something simple stupid that i just forgot to try. is there anything you all might try that i didn't?

73hdsporty
05-08-2008, 05:26 PM
UPDATE:::: well heres what i found out fro the guys at the ironhead sportster garage fourm and from a local macanick.
1. the Spyke Igntion coil with three therminals and two spark plug connections. your ignition is probably set up for Single Fire and has both coils integrated in one package. In which case the plugs will not fire at the same time
2. you can use a spyke 3 therminal coil with a Crane HI4 if you jump the two negitive terminals with the black wire that comes off the Crane HI4.
But I Still Haven't Figured Out How To Test The Spyke Ignition To Know If Its Bad Or Not, Does Anybody Got Any Ideas On How To Do This??