[Othello]

I have a 1990 EX500 that sat for about 8 years before I bought it. Cleaned the carbs, replaced the plugs, new air filter (K&N) rejetted the carbs after installing the filter. The bike runs very well, except for it dying intermittently.

I can start the bike when cold, and 9 times out of 10 it will run flawlessly until I turn it off. The next time I start it, regardless of how soon, from immediatly to hours later, it will die after running for a few minutes. The tach will jump all over the place, and it usually backfires, then dead. the lights all still work, the starter will turn the bike over, but it won't start for a few mins. Usually it'll start again within a minute or two, (sometimes it will backfire while trying to start it again) then run for a minute or two, then die again, then wait, then start, then die... after doing this a few times, it'll run fine again until the next time I stop it.

I also have a 93 500 that my sister's boyfriend managed to crash into a parked car, so I bought it cheap to have spare parts. Previously I got a whole wiring harness off of ebay, so I've already replaced the Ignitor, coils, Rectifier, and junction box (maybe more, can't remember) but I can't verify that they came off a running bike since they came from ebay, although since the problem is the same, odds are good.

I saw a suggestion in another thread to check the ground, which I will do when I get home, but I thought this seems a little too predictiable to be a loose connection?

Any suggestions would be VERY appreciated, this is going to be my wife's bike now that I moved up to a '03 636, and I want it to be reliable for her

 

[Imposter]

Could it be dead or dying battery? Or maybe the spark plugs are not seated correctly at the right depth? How is the idle?

 

[Othello]

The battery is new as of 2 months ago, and I have a battery tender on it most of the time.

The plugs are fairly new, and I just got the stock NGK plugs, they are seated completely.

The idle is completely smooth, and doesn't fluctuate. It also starts VERY easily when not having this problem.

 

[Imposter]

Sounds like a ground to me now also. But I could be wrong, but you basically covered everything else. I would check any new connections, light harnesses, alarms, anywhere where the wire come close to screws or braces, and places where water or humidity might come in touch with exposed wire parts. Was any electrical stuff done lately, new turn signals or brake lamps? Maybe LED's?

 

[Othello]

nope, nothing new.

I just find it odd that it doesn't do it more often if it is a ground, which is why I though it was a component. Oh well, off to the garage I go. I'll let you know if I get it fixed

Thanks

 

[ZX-2R]

SOMEONE

Someone complained about plug wires being defective...anyway find a dark garage or a dark evening and start it up and look for any arcing, then start spraying from a water misting bottle till you get everything wet...if tha ttdowsn't find a problem I'd definately expect you to find a ground that is dirty on it. temporarily run an aligator clip from the engine to the battery...for ground...sounds crazy...just try it, see if it helps....

 

[Cale]

Did you try the ignition kay switch?