1985 GPz550 cranking but not starting, shows 10v

Hey guys, first post here! I just picked up a black/red 1985 ZX550 GPz. When I went to go pick it up it ran pretty mint, albeit it sounded like the carbs were a little out of sync. I brought it back to my place and rode it around for the better part of a day before putting it away. Each time I pushed the ignition button it started right up in one crank, no problems whatsoever. It was awesome!

Then it rained that night.

Now it won't start at all I don't know what's up with it, but I'm pretty sure it's electrical. It just cranks and cranks, but won't fire. Occasionally it'll pop off a massive fireball after I've cranked it for a couple seconds, but nada besides that. I got it to start once on a fluke, but it ran really rough and wouldn't rev past around 5 grand. The voltmeter on the tachometer reads 10v no matter how much I charge the battery.

I'm pretty sure my battery's good, as the charger I have has no problem charging it and isn't detecting any problems. I'll pick up a multimeter tomorrow to verify that it's actually putting out 12v power and to check other things though.

Besides that, I'm kinda lost. This is my first bike; while I've dealt with cars a lot, I'm pretty new to the systems here. I'm hoping you guys can help me troubleshoot.

Ok, so here are some details on suspicious components of the bike:
- The side body panels are missing. This leaves some of the electronics exposed to the weather, which reinforces my theory that it's something electrical in that region.
- Battery looks newish, I don't believe it's bad (what's the red wire (not the positive terminal lol) that sticks out of the top though? I have no idea what that does, but the connection broke and I haven't put it back together yet.)
- The ignition box looks to be in decent shape, but has some rust on the metal backplate. Connector looks good.
- The regulator (the thing with vanes bolted behind the fuse box?) is very corroded and oldish looking. The connector looks fine though.
- Coils look fine, don't believe it's these.
- Plugs are newish, look fine.
- Plug wires are old, but the bike was working fine before so I don't think they'd be an issue.

If anyone could provide any guidance that would be awesome, it's amazing out and I really wanna ride already!

Anyone? I tested the battery today and it's reading 12.15v between the terminals, so I know it's good. For some reason the voltmeter is only reading 10v though. Still won't start; it'll crank all day though. What could this be? The regulator?

Some places to look:

1.These Kawasaki's have a 5000 ohm, non replaceable resistor on the sparkplug caps, which go bad from heat,vibration and age. They can be checked with a multimeter, but you're better off replacing all of them. www.z1enterprises.com sells new ones, along with most Japanese motorcycle shops.They unscrew from the sparkplug wires, when installing new ones, cut about 1/4" off the sparkplug wires for a better connection, as corrosion will affect the spark.

How to use a multimeter:


2.If you have the stock igntion coils, most develope cracks, letting in moisture, possibly shorting out the ignition coils. If you think yours are as old as the bike, again, ask at Z1 for advice about possibly replacing your coils.

It turned out to be the ignition box. It was half full of water. :blink: Emptied it out, blew some compressed air in there, let it dry, and now she runs mint! Extremely surprised it didn't blow anything up or light itself on fire... Thanks for the pointers though!