Bike dies suddenly, electrical issue?

[KJ790]

Hi everyone, I'm trying to track down what I think is a bad connection somewhere. The bike is an 81 XS650, all stock. It runs great, but every once in a while it will just shut off while riding, as if someone just cut power to the ignition, no stumble, no hiccup, just shuts off. The lights and everything stay on the whole time, it is just the ignition that dies. I coast to a stop and it always fires right up. It typically does it about once every 100 miles or so. I think it may be a loose connection in the handlebar shut-off switch, but I can't get it to do it when I want to, and since it always restarts right away it is pretty hard to trouble shoot. Is there anything that is common on these bikes that will cause these symptoms?

 

[jayel]

the kill switch as you mentioned, the clutch switch, and if a late model 81 might have the side stand cutout and of course the TCI itself

 

[KJ790]

the kill switch as you mentioned, the clutch switch, and if a late model 81 might have the side stand cutout and of course the TCI itself

Thanks for the reply. This bike doesn't have a side stand switch, so that is out. I will have to look into the clutch switch, would this make it die once it was running?

This reminds me, when the bike dies and is coasting, if I pull in the clutch and hit the starter button it does nothing, but when I come to a stop, put it in neutral it fires right up. I haven't had a chance to try to find neutral and hit the starter while still coasting however.

 

[jayel]

your clutch switch and neutral do share a connection thru the starter cutoff relay so it's possible

might want to research threads on the TCI and replace the diodes retouch the solder connections, good insurance to eliminate a potenial problem

 

[littlebill31]

The kill switch might need a good cleaning inside. I had a dirty kill switch and it did the same thing. Dirty kill switches also cut power by touching them just a little, inadvertently, with your thumb while riding.
I would also check your ignition switch as well. They too can be very touchy. My '81 would cut power and it took me forever to figure out it was the ignition switch tripping when I hit a bump. I would get it running then just barely touch the key and it would shut off.

 

[KJ790]

Thanks guys, I'll check it out. It's just frustrating because I can not duplicate it by touching any of the switches with it running in the garage. It only happens while riding and only once in a while, so it is really hard to track it down.

 

[Dennis]

so maybe since you cant find it in the garage, which I would assume you would be in neutral. you know a good place to start with the above posts

 

[jamesgs4]

I had the exact same problem. The fuse boxes on that year are huge pieces of shit. It is best to replace the whole thing or eliminate it completely.

 

[CafeKings]

Im having the same problem with my 1981 xs650 hase new key switch and kill switch so still does it