No spark - think it's the coil

[SDLars]

You fellows helped me out a few weeks ago with a charging issue on my '81 XS650. I replaced the rotor and everything has been fine for the past few hundred miles. Took it out on about hundred mile run yesterday. All was fine until I got about two miles from home when it just died. No warning, no indication of it having any other kind of problem. I replaced the fuse block when I did the rotor so I assumed that one of my connections had come loose; not the case. I started checking connections, etc. and got to the coil. There's power to all places that are supposed to have power. I put the ohm meter on the coil and got crazy readings. It's like it won't settle down to a single number. It has read anywhere from mid 4's to over 100. Haven't checked the new rotor yet but my voltmeter was reading in the 13+ range just before she died. Order a new coil or is there something else I should be looking at? Thanks in advance for your help!!

 

[mrtwowheel]

Have to ask the simple questions, When you are testing the coil, are you pushing and drilling the leads into the blade connectors? The reading will do just as you describe unless you use some force and twisting motion to get a good connection and reading (the lowest reading), same at the rotor, but at the same time, don't chew up the surfaces of the rotor rings real badly with the leads.

Scott

 

[SDLars]

I wasn't aware that the meter would do that. I think I had good contact but I'll try again and check back. Thanks.

 

[SDLars]

Have to ask the simple questions, When you are testing the coil, are you pushing and drilling the leads into the blade connectors? The reading will do just as you describe unless you use some force and twisting motion to get a good connection and reading (the lowest reading), same at the rotor, but at the same time, don't chew up the surfaces of the rotor rings real badly with the leads.

Scott

Put a different meter on the contacts. Checks out at 2.9. Got interrupted so still didn't get the rotor checked. Back of rotor/stator cover seemed dirtier than it should have been.
More to follow.

 

[SDLars]

Got a different multimeter and now the coil checks out at 2.9. Took the alternator cover off and found brass shavings inside. The rotor looks to be shelled and although I haven't taken things apart, the stator windings don't look so good either. That rotor doesn't have 400 miles on it yet.
More to come.

 

[SDLars]

Took things apart. Rotor and stator are actually OK, I think. Small amount of brass shavings inside cover looked bad but can't really see where they may have come from. Think I may be getting a small amount of engine oil from the drive sprocket/shaft. Maybe new seal time? Here are my ohm readings: Rotor - 5.3; Primary coil - 2.6; checked the pickup coils across the two contacts and get 9.4. My Haynes manual says the pickup coils should read 700 plus or minus 10%. Did I check in the correct place? Not sure how to check the secondary coil? According to those readings, if I was checking properly, the pickup coils gave out? Thanks again for all your help.