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Last week I rode my 79 FXS for the first time and it ran great. Put 10 miles on it, but needed a new battery. I put the new battery in on Thursday and on Friday morning it cranked but wouldn't start. Ether didn't help so I figured I had an ignition problem. Today I first checked for power at the coil, it was good. Then I pulled the 'points' cover and the LED was flashing on the Optima ignition when it cranked. Then I pulled a plug and found no spark there. Tried the other, just to be sure, and no spark at all. Bad ignition unit? It has maybe 20 miles on it, back in 2015.
Next thing to do is temporarily put the points back in:
That did it! It started up and ran, but not well. I adjusted the points gap to .018 and the timing to the F mark, and that helped, but it still wouldn't take gas and misfired if I sneaked up on it. I got the timing light and re-adjusted the timing (it was off) and it was better but still not great. I verified the advance was moving too. It idles well but a quick ride confirmed it was misfiring up to about 1/4 throttle. So now I'm at a crossroads. Do I keep fiddling with points or buy another ignition module? If it ran well with points I'd leave them in, because they won't leave me stranded like the electronic almost did. Any suggestions on what the points need? I am still using the 3-ohm coil, but that shouldn't matter in the short term, right? I found a new blue streak condenser made in mexico in my stash, but it didn't make a difference. I also closed the spark plug gaps to .028, by memory.
you set them don't know how you did it but just the way we do it might help -- on the line for full advance front cylinder ( blow air in rear plug hole to check that has a valve open ) and turn the points rubbing block to full advance - and with the points adjusted correctly - and a plug connected to the coil and grounded - just as the points brake at full advance and it sparks tighten the plate screws
I would take the coil off and pop it in the toaster oven to bring it up to about 140* to see what the resistance reads hot.
It could be the root of the problem, or not. Just part of the process of elimination.
Last edited by 78lowrdr; Sep 23, 2018 at 07:51 AM.
The coil is brand new Twin Power coil, not the one that came with the ignition system. I know to use a 5-ohm coil with points, but it should run OK with the 3-ohm, except it will eventually cook the coil, or burn the points, right?
As far as timing, I used a timing light on the marks I made on the alternator cover, and the timing is advanced a little, so I'll tweak it again. I'll let you know what happens with that.
It ran perfectly with the Optima ignition, with just a couple of coughs in the last mile, then it didn't run at all.
It's a lot better now - I retarded the spark a little more - but didn't have ambition today to pull the side cover and check it. Tomorrow I'll get a buddy over and he'll help.
I also noticed the exhaust was smoky so I turned in the idle screw almost a full turn - that made the idle a lot higher and also got rid of some of the misfire.
So little by little it's getting better. It still ran a lot better with the electronic ignition so I'll probably get another one.
Does anyone know how to get ahold of Bill "Chopprs" from the other website?
American Motorcycle Parts
1435 Best Road
East Greenbush NY 12061
518-459-8819
Back to my problem, I used the timing light and got the timing exactly on the F mark. It starts and idles great, but still misfires when taking off or cruising. Opening the throttle above 1/4 or so and it runs good too. Any ideas on what to do next? Here is a video so you can hear what's going on.
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Ignition Problems
