Topic: do i need new coils?

[jvalbuena]

Just got back from what was to be an 1800-mile trip from Chicago to Memphis following the river. Made it there and about half way back then the bike started running like crap. Basically, it was running on 3 cyl. Number 1 is not working. I tried swapping the resistor caps on 1 and 4 to see if that was the problem and it's not. I cut about 1/2 inch off of the plug wire and screwed in the resistor cap and that didn't work either. All the connections to the coil look ok (I disconnected cleaned and reconnected them all). I replaced all the plugs and limped it about 5 miles into the closest town and when I pulled the plugs, all looked fine except for #1 which still looked brand new. Is it strange for a coil to fire one plug ok but not the other (one coil fires 1 and 4, the other 2 and 3)? I actually checked for spark (put a plug in each and grounded it to the case). All showed spark but #1 was barely visible. Gas is definitely getting to all cyl because I can smell the unburnt gas in the exhaust. Any suggestions for replacements? I'll post pics from the trip when i get them back. It was fantastic up until the break-down.

[TwoTired]

Carefully check number one's ignition wire along its full length for cracks.  Usually right at the coil it cracks and arcs to some nearby piece of metal using surface contamination in the area as a conduit.  A darkened garage would show this as a light show.  If the insulation crack is not too old, and the wire inside has not corroded yet, you can clean the area with acetone, goop it with RTV and slide heat shrink tubing over the crack.  This should prevent further leakage. 

Or, you can replace the coils.