TOPIC:

Hey Everybody,
I had a little problem with my KZ750 while riding home the other day in light rain, Cylinders 2 and 3 stopped firing! I have determined it to be an issue of spark, getting none on those two cylinders, so I figure it must be that ignitor coil. Ordered replacement, not a problem to fix.

My question is this, what could have caused the coil to blow?
A few weeks ago I got caught in the rain, my bike did the same thing, then blew the main 20 A fuse, I replaced the fuse, and the bike ran fine.

I got it home and hunted down a short in my starter button assembly, the wires had become exposed and melted together, so a friend (Limey from this Forum) helped me re-solder the wires into the assembly and heat-shrinked them separately where needed. Bike ran great for two weeks (almost 800 miles) with no problems.

I get caught in the rain literally just a few drops on monday, and my coil blows, unlike before, the fuse did not blow. I checked the wiring in the starter assembly, everything is as it should be there, no fraying, etc.

Any Ideas? I don't want to keep buying coils.

Thanks,
Mike

Mike: Have you checked your points?

It is possible that the insulation in an old coil was starting to break down, and moisture helped cause a short which could both blow the fuse, and stop the spark. I'm not sure if your bike has points, but if it does, one pair not opening, or remaining open, could also cause the same problem.

Have you checked the coil resistance?

Sometimes in rain the coils short out, the location under the tank has something to do with it. By any chance is the coil cracked, allowing water inside? Maybe a blast of WD-40 on the coil will displace the water

The bike is stuck out at my brothers house in West Broomfield, for an engineer, he doesn't have many tools. My resources in solving this problem were limited but a friend needed the right coil for the same bike so ordered a pair together online for a good price.

I hope I can get it home somehow this weekend, and then I can do some more investigation.

I can tell you almost for certain that this problem is rain related, it started within seconds of the rain both times.

I appreciate the input guys, I am trying to make a 1,000 mile trip on this bike in july, and with these frequent electrical problems, it's not looking to positive.

I have a can in my garage called "Wire Drier" from a company called SPARK. I bet it acts like WD-40 and displaces water. Maybe something like this is what you need to spray on your coils or plug wires. Something is shorting out when it rains.

MikePotter86 wrote:

The bike is stuck out at my brothers house in West Broomfield, for an engineer, he doesn't have many tools. My resources in solving this problem were limited but a friend needed the right coil for the same bike so ordered a pair together online for a good price.

I hope I can get it home somehow this weekend, and then I can do some more investigation.

I can tell you almost for certain that this problem is rain related, it started within seconds of the rain both times.

I appreciate the input guys, I am trying to make a 1,000 mile trip on this bike in july, and with these frequent electrical problems, it's not looking to positive.

When you get it running, bring it over and we can go over all the electrics, ignition etc. - basically give it a physical! That way you will be in good shape for a long trip (and I do have the tools)!

If you can't get it running, give me a call - I just bought a trailer!

Eric,
Thanks A lot, I will do that as soon as I get it running. God willing it will be Monday, maybe we can look at it on the weekend, whatever works for you.

Be careful of using WD-40 on electrical contacts such as switches or plug in connectors and fuse clips.

I had an occasion where I went to start my 1982 GPZ1100B2; I turned the key and no lights,fuel pump sound,horn just nothing. I was fortunate to have some fine grit sandpaper in my tool kit and I roughed up the fuse clips and got home o.k. I later took a dremel tool to the fuse clips with a wire wheel and removed the WD-40 that became non-conductive.

I have since used an electrical contact/preservative from Caig laboratories(sp) called deoxit. You can get it at www.deoxit.com the spray or brush on cleaner is save for plastics ans will reduce/eliminate electrical contact problems.

I replaced the coil on Monday, and everything is running fine. Eric (Limey) is going to help me look to see if another problem caused this tomorrow.