Headlight melting plug! HELP!

This is the second plug I have had to replace. I checked the voltage with the bike off and with it running and it reads 14.5 volts at the plug. I had replaced the original headlight with one that had built in LED blinkers. It was cheap off EBAY so I thought maybe the bulb was funky also. The first plug I replaced I had been running with my high beam on so I thought it must have generated to much heat. That plug was stuck so bad it actually pulled the bulb apart getting the plug off. I replaced it with a Sylvania bulb that's supposed to be brighter. This time I managed to get the plug off without destroying my $20 bulb. Everything was fine yesterday, I rode about 120 miles round trip to a bike show. Later in the eve I was working on the bike and noticed that the headlight wouldn't come on so I pulled it out and discovered the plug had melted and the terminal came apart. So I replaced the plug with one from Autozone and in the midst of checking the voltage I dropped the light and busted the glass out of it. Back in goes the original light and bulb. I just cant figure out why its melting the plug? The choke was on when I tested the voltage so it was probably around 2000 RPM? Should I run it higher and re check the voltage? Thanks for any replies that may sort this out. Here is a picture of the plug I replaced.

A few things:

1) I would IMMEDIATELY check the battery voltage when revving the engine up to over 3000. It should not go higher than about 14.5V. If it goes much above that, the voltage reg is bad.

2) Things melt from heat and it could get too hot for several reasons:

Bulb is too high Wattage rating.

Something wrong with the bulb, drawing too much current.

Connector terminals dirty or not making tight contact. That increases the contact resistance at the connector and things get very hot when that happens.

If you have an Amp meter, you could measure the headlight current draw.

OK, I think my meter has an amp setting. Check it with it running I guess? The bulb is a regular H4 bulb.

If it's like this:

www.1000bulbs.com/product/55231/Q-H47570...q0j78CFQaBfgodm7AA1A

could be too much Wattage. These old KZ's were designed to run a low beam of about 40W and a high beam of about 55W.

The 82 KZ1000-Ltd came stock w a 60/55W halogen headlight. I wouldn't go any higher than that. Otherwise, you'd have to make some changes to the headlight circuit (thicker wire, relay, etc). Since the thing has melted, you might need to check the wiring to see if it needs to be replaced.

Thanks guys. I now have the stock bulb back in it so I will keep an eye on it this time. The rest of the wiring is fine.

I'd get some De-Oxit electrical contact cleaner/preservative, and clean the headlight bulb, and socket contacts, as it looks to me, to be corroded, increasing the current draw, creating heat.

www.deoxit.com is their website.

I also think it may be due to crappy connection. It doesn't increase current draw, but it dissipates power at the connection site. The power dissipated is the current (squared) times the contact resistance. In a 12V system, currents run high for just about everything so it doesn't take much contact resistance to start cooking a connector.

Replace that headlight connector. Most any auto parts store should stock it. Or cut a good used one from the wreckers for cheap, possibly free. Solder the connections made and heat shrink them.
Make double sure of the Bulb Wattage, it is stamped right on the bulb base.

All the connections were tight and not corroded. That plug was in good shape when I replaced it. Yes Motor Head I got a new plug at the parts store to replace the bad one.

Your local auto parts should also carry high temp plugs that should help.

Motor Head wrote: Replace that headlight connector. Most any auto parts store should stock it. Or cut a good used one from the wreckers for cheap, possibly free. Solder the connections made and heat shrink them.
Make double sure of the Bulb Wattage, it is stamped right on the bulb base.

You might want to take a scotchbrite pad to the male terminals on the bulb and make sure they are clean. The other thing I'm not sure on is whether that type of bulb needs a heat sink? If it gets hot enough to melt a connector, makes me wonder.

Other biggie: make sure the system voltahe is regulating at 14V when running. If the regulator is not working the voltage will rise. Bulbs get VERY hot since their power dissipation goes up as the voltage squared.