Wet weather problem

XJ 700N, 1985, 21,000 miles, bone stock. The bike has been running perfectly. It rained today and the bike was uncovered while at work. The bike started and ran perfectly for about 15 miles, but when I slowed down for a red light it cut off. It was raining lightly and the road was wet. After about 10 minutes and several attempts it started and I road home, about 15 miles, with no issues. Now it starts and runs normally. I am thinking that something is getting shorted out by water from the road or rain. My first thought is a cracked coil but it could be something else since my first look at the coils didn't reveal any cracks. Anything else I can look at? Anyway to test the coils with the engine running?

 

check if the drain holes for the spark plugs ar'nt blogged up with muck, particularly #2 and3. they could be filling up with water and shorting the plug out

 

While the bike is running spray a fine mist of water on the coils. After years, the stock coils have been known to develop hairline cracks from the heat of the engine.

 

I will take a look. I know the outside plugs were dry.

 

Thanks. I will try that in the morning. Got to get a good mister anyway.

 

Do it after dark and you'll see exactly where the stray pixies are dancing off from.

 

Have you been watching AvE on you tube?

 

Good idea. I'll wait until tomorrow night.

 

Often.

 

I finally got around to checking for shorts. Removed the coil covers and sprayed (misted) water all over them until water was dripping off. Did this all in the dark. No sparks, no stumble, no nothing. Drenched the plug wires and caps with the same results. Drenched the ignition switch and cut off switch with no issues. Even drenched the kickstand switch. So, maybe I don't have an electrical problem. When it happened I was coming to a stop and it just cut off--no stumbling or misfiring. Almost like I cut it off with the key. So--any ideas what to check now?

 

my guess , after all other considerations ,the ignition switch being out in the rain all day might have something to do with it.

 

why? cause it happened when you were braking .water droplets inside sw act like a mercury sw under braking g's. shunting ign. temporarily. hard to replicate. -- a guess.

 

That's a good a guess as I've been able to come up. I hate electrical problems.

 

Some WD-40 sprayed in the switch might help keep the moisture out. Put the key partially in and spray it.

 

Good idea. Probably spray the kickstand switch also. Right now it's running perfectly, but I have lost a little confidence in it.

 

I had a similar problem on my Honda CB750K2 years ago when it was raining. Spray the electrics and give it a few runs in the dry it should be fine.

 

It's running perfectly now, but I am going to give everything a light coat of WD-40.

 

Remember WD-40 chases water away, but then attracts dust buildup which will trap moisture later....

 

Good point. So, what is a good option?

 

Only spray where needed and wipe off excess.

 

I use it to get rid of moisture, and follow up with contact cleaner. Make sure that the contact cleaner fully evaporates before hooking things back up and turning on the ignition.