1982 XJ650 Maxim runs poorly in the rain

Anytime my bike gets wet, it seems like one or two cylinders begin to misfire. I first noticed this issue after first washing my bike, not with a pressure washer, after restoring it. Even after letting it dry for an hour, it would be very difficult to start and was definitively running very poorly, but once it dried off it would run just fine. I haven't really worried about it as I try to avoid riding in the rain as much as possible. Last season however I got caught in a downpour and I was severely down on power and barely made it home. Now just last week I rode through a very light rain (more like a drizzle) for only a couple minutes and the same thing happened. When I stopped at a light and drove off the engine stumbled and struggled to accelerate. I can only guess that this is an electrical issue, but I'm not sure where to start. I've read that a cracked coil housing could do this, but I can't imagine any water got up there from that amount of rain and I can't see any obvious cracks. Any help would be appreciated to find a good place to start.

 

I would guess a bad plug wire. Once things are wet, try spraying WD-40 on the wires & coils sparingly so that you know where you sprayed.

WD-40 (Water Displacement attempt #40) will move the water away and hopefully restore the electrical connection

other than that, remove each lug wire & examine

good luck!

 

Thanks for the suggestion, what do you mean by "remove each lug wire and examine?"

 

Just pull the wire off and inspect the boot too see if water could enter there.
A cracked plug wire would be more likely than right at the spark plug I would think tough

I've had this kind of problem on an old car, but not a motorcycle

 

If two cylinders are not firing I would think it's the coil for that bank. My XJ650J did the sane thing. The coil had a crack in it. I also had issues when it was damp or humid.

 

Yes more likely to be the coil. You can also start the bike at night and see if the sparks are visible, may be tracking onto the cylinder head. This is unlikely though to have two caps doing this at the same time.

 

Or spray some water from a spray bottle on the coil while running.

 

Yes indeed I forgot to say a rainy night good observation.

 

Most likely a coil. It’s a common, known issue. When you have the coils off, you’ll probably see a crack right down the middle between the two long humps.

 

I would put my money here too, I had same bike and same issue, was cracked coils. Everytime I got stuck in rain it would start to misfire and stumble. Even in a light rain water will blow back between the tank and frame and run down wires etc. to the coils area. Takes awhile to dry out and run correctly again because the water works it way down into the crack.

 

Alright, I will take them off and look at them a little more closely. Another electrical issue I've been having, is that sometimes when I hit the starter button, it takes a few seconds for the starter motor to start cranking. Maybe 10% of the time I will have to hold the button for 15-30 seconds before it actually works. If I let go of the button before it starts cranking, I can hear a relay or something click. Could this be my starter relay starting to go out?

 

Pop the side cover off and put your right hand on the starter solenoid and press start with your left hand. If you can physically feel the solenoid clunking then it may be the solenoid itself. I say maybe because it could be the starter too that needs cleaning or brushes replaced.

 

That is often an indicator of a weaker battery, too

 

Well would you look at that, two big cracks in the same spot on both coils. What should I use to seal those up, Epoxy?

 

I don't have experience with that but epoxy may work. I think I would force silicone caulk into the cracks and then cover with a flat bead of silicone. Waterproof and vibration proof but epoxy may be better at preventing the cracks from possibly growing.

 

Yes, or outdoor weather caulking .....but make sure they are dried out really thoroughly first....you sure don’t want to seal any moisture in while you’re trying to seal it out!

 

Correct, that is what heat guns are made for.

 

Sweet, I think I will try using some epoxy and hopefully that will keep me from getting stranded if I get caught in the rain! Also, while I had the coils off, I unplugged them to work the starter without it actually starting. I had the wire harness grounded between the frame and one of the coils (not sure if that is where it is supposed to be). I bolted just the ground back on to the bare metal and the starter is now working without fail. Not sure if this is just coincidence, because sometimes I don't have any issue. Should I be grounding the wire harness to a different location?

 

That is where the main harness grounds. It is the only ground for the harness on that bike, if the connection was poor you'd have issues with starting, lights, etc. I ran an additional 12ga ground wire from that connection down to another ground point by the TCI where the heavy ground wire comes off the motor. Not necessary but both ground points need to be clean connections. I had my frame powder-coated and was initially perplexed as to why nothing worked.

 

Just to be safe I hit the cracks with the blow dryer for a little while, and put decent layer of quick setting epoxy over the cracks. Ill give them 24 hrs to cure before putting them back on. Never thought I would say this, but there is rain in the forecast for Saturday so I'll try to go for a ride and test it out. Thanks for all of the suggestions. I will update with any success or failure.

As for the starter issue, I was thinking of replacing my cheap lead acid battery with a sealed gel battery so maybe I will do that and see if it helps. If that doesn't help I'll just replace the starter relay.

 

also clean the wires and connections on solinoid for the battery and starter the large nuts.

 

These coils will fit on the 80-83 XJ650's:
https://www.dbelectrical.com/produc...aki-kr1-suzuki-gsf1200-yamaha-fzr-others.html

 

Hope you got all the moisture out....

its snowing here again....

 

Alright so update on the starter issue. Today I was trying to see if I could feel the relay clicking when it wasn't turning over, which it does. When it doesn't work properly, it will click very lightly and after holding the button down, it will eventually click again and the starter will begin to crank. Seems like maybe the relay is sticking and I should replace it?

 

Did you check battery under load yet

 

I have one of those battery testers that puts a load on the battery, I tested it before putting the battery back in when dewinterizing and it was on the low end of "good." Is there a different way that I could potentially rule out the battery? I may still replace it anyways, but if I can hold off until I can go back to work, I would prefer to do that.

 

Hold it up to the bike, read the standing voltage, and then watch to see what the voltage stops to when you engage the starter

 

This product is currently unavailable.

 

The voltage when I started was 12.6 V. When the key was turned on and neutral light illuminated, the voltage dropped to 12 V . When the starter is cranking, the voltage drops to 8.5 V but only for a split second before the engine actually starts. When the relay gets hung up while holding down the button, the voltage was unchanged, still at 12 V. The voltage while running with the headlight on was 11.8 V.

I'm going to fully charge the battery and see if I get better numbers, but it's looking like a new battery may be in order.

 

Weak battery and your system isn’t charging

 

Running voltage looks to be way too low. Check voltage while revving the engine to see if the battery is getting charging voltage (around 14.5V). If it is not charging, a new battery will just run down also.