Maxim shuts down once it rains

Whenever it rains my Maxim sputters out and completely shuts down.

After it sprinkles-it sputters, but after it rains moderate to heavy my Maxim completely dies. Then after is dries out it runs perfectly...any ideas? Trying to reach out to the forum to see if there is anything specific to these motorbikes I am not aware of. Just some highlights:

* The wires are very dry- nothing is bare or short circuiting

* The engine turns but won't "catch" or "spark"

* There is plenty of fuel

* '85 Maxim Yamaha xj700

* Once it dries out in sunshine, I am good-to-go

Thoughts?

 

I had a similar issue on my maxim x and found that one of my air box to Carb boots wasn't sealed around the Carb completely. Just something to check...


Edit...also check your plug caps. I couldn't get mine to start after washing it once... blew out the caps and it started fine

 

Wet coils. Next time that happens, soak the coils down with WD40 or some other water-chasing thing like that..... and see whether you're able to get it starting to sputter back to life as the water is evacuated. You could even just take a close close look at the coils and see if there is a visible lengthwise crack running between the two wire leads and along the bottom of the coil. Easy for water to get in there. Its a COMMON issue. These coils are notorious for that.

Dave Fox

 

when you say the coils what do you mean? Sorry I am not a mechanic but know the basics

 

Ignition coils.

 

follow the four spark plug wires from the plugs up and back to the 'slightly larger than D batteries' thingies that the wires come out of. Two wires will come out of each one. Those two 'thingies' are the spark coils. The cracks often develop between the humps that run the length of each coil.

Dave Fox

 

Hi gang.....well when i pour water right above the tank, below the gauges the bike shuts down. It is not when i pour water on the side of the bike. I put electrical tape on all exposed wires.

But the bike still stops running when water is poured here.

 

Try getting to the coils, cover them in plastic bags, and then pour water there again when running and see if it still stops.

 

coils are cracked

 

Yep, your coils are right below the gas tank. They're cracked. You'll have to address it if you want to ride in the rain.

 

well now you know the issue at least! perhaps some goop to seal them up? its pretty much a highly adhesive caulk. and flexible once dried. plus you cant see the coils so its not like you have to worry about it looking so pretty, lol.

 

just a heads up I wrapped them in plastic and it looks like this worked

 

Yeah, that's about as isolated an issue as you could hope for!

Out of curiousity, everone--why do coils crack? Is it just the outside casing that cracks? Is it just as simple as sealing the cracks, no other problems? Does letting water in lead to long term damage?

 

The coils are big lumps of cast plastic; as it ages and dries out, cracks can develop along "molding fissures" running through the plastic.

It's not a matter of the casing, it's the coils themselves.

Yes they can often be effectively sealed; and if left internally "wet" long enough, they could become compromised.

 

If I may probe the higher minds here... What exactly are coils, then? How do they work? All I (think that I) know is that they take the system's DC 12v at a couple amps and change it to several thousand volts of AC at very low amps and send it to the spark plugs, which need high voltage to arc across the tip of the plug and light up the cylinder.

Now if it's just plastic, then I'm confused--how is that being accomplished?

 

Correct. Basically, a step-up transformer.

Plastic casing. The actual transformer guts use lots of wire.