I had the same problems, but coincidence was it started as soon as I changed to the Unifilter pre-filter. So the bike ran sort of crappy and was backfiring and would then cut out - making it tough to decipher if it was the ignition/electrical or the carbs...
Did some tuning on the carbs, which helped the bike run better but it still cut out and would only restart if I turned the key off and then on again. After reading this thread I changed my tactics to start and would hold the starter button in and wiggle and giggle the key - it would start right up!
I figured I would order the new start/key mechanism... but figured I would open it up first as I figured it was toast anyway.
The good thing is you do not have to move the entire mechanism and the bottom 1/3 of the key/barrel comes apart with the electrical section coming off.
Electrical section removed - 2 philips screws takes it off - simple.
Sorry for the poor colour saturation - bottom electrical 1/3
The bottom portion comes off, you will need a screw driver to push in the lock tabs and then cut the zip tie, pulling it down reveals the underside of the electrical connections:
Then, more plastic tabs and you remove the section with the electrical contacts, this is 2 pieces.
The bottom piece is fixed and has the contacts to the wiring harness and starter. As you can see it is pretty gummed up. The grease that they use has hardened and I do not think allows conduction anymore.
The top piece has a hole in the top that the key turns via a shaft making contact with the contacts depending on its location, the bottom of this piece was also covered in the dried out grease. This should be shiny.
I cleaned both pieces up, what I noticed was that the bottom section with the stationary contacts one of them was fairly low down and has me thinking that this might be the culprit. The contact in the centre at the back, you can just make out the right side of it is higher than the left:
It crossed my mind to put a drop of solder on it, but knowing my luck I would overheat it and ruin it, but, the contacts from the top piece that point down are all spring loaded so there should always be contact.
I had to take a break and forgot the camera when I returned so no more pics... but I put it all back together again, no problem and so far with 2 short rides (15min each) no more cutting out. It had gotten to the point that even warming up the bike at idle it would cut out... so I think it is all good now!
Tomorrow I will get a longer ride in and see how it goes.
I know not as detailed as a Pyndon write up, nor as exciting as Flannyvision, but you get the idea!
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