Hot fuse problem.
- built408
-
Topic Author
- Offline
- User
-
Registered
- Posts: 56
- Thanks: 0
Hot fuse problem.
17 Oct 2012 19:08
I'm having a strange issue with my electrical system at the main fuse (the one with the white wire) It's getting HOT. With my ignition on and bike running or not it's fine but when I turn my headlight switch on it starts to get hot. I checked the wires coming out by the bulb and I get between 14-15 on the volt meter. With the head light off it's fine . I can't seem to figure it out please Help!!!
Also My bike has the h4 conversion.

1978 KZ1000 A2A with MKII body you know you like it
Please Log in or Create an account to join the conversation.
- RonKZ650
-
- Offline
- User
-
Registered
- Posts: 3711
- Thanks: 247
Re: Hot fuse problem.
17 Oct 2012 19:38
The fuse always runs hot, but how hot is too hot is the question. The more current the fuse is flowing the hotter it will get, so headlight draws 55w or whatever, that is more current to push the heat up. Very common problem and only one explanation despite other possible fables, and that is the fuse clips have bad connection to the fuse. This can sometimes be fixed by polishing and cleaning the fuse clips till they are bright and shiney, sometimes not. Guys change to modern blade fuses to fix the problem right. I tie the fuse tightly to the clips using zipties to put pressure between the clips and the fuse if cleaning doesn't do the trick.
321,000 miles on KZ's that I can remember. Not going to see any more.
Please Log in or Create an account to join the conversation.
- 650ed
-
- Offline
- User
-
Registered
- Posts: 15333
- Thanks: 2833
Re: Hot fuse problem.
17 Oct 2012 19:48
What is the wattage of your H4 bulb? If it is higher than that of the stock bulb things will get hot. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Please Log in or Create an account to join the conversation.
- built408
-
Topic Author
- Offline
- User
-
Registered
- Posts: 56
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 19:51
I'm talking melting plastic hot!!! I'll try the polish trick my fuse is held in tight so I know its not loose
1978 KZ1000 A2A with MKII body you know you like it
Please Log in or Create an account to join the conversation.
- 650ed
-
- Offline
- User
-
Registered
- Posts: 15333
- Thanks: 2833
Re: Hot fuse problem.
17 Oct 2012 20:04built408 wrote: I'm talking melting plastic hot!!! I'll try the polish trick my fuse is held in tight so I know its not loose
I know (see pic). That's why I asked about the wattage of the H4 bulb.

Attachment BurntConnector.jpg not found
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Attachments:
Please Log in or Create an account to join the conversation.
- 4TheKZ1000
-
- User
-
Public
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 20:04
the H-4 is 55-65 watt while stock incodesent was 50-60 watt
Please Log in or Create an account to join the conversation.
- 4TheKZ1000
-
- User
-
Public
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 20:13650ed wrote:built408 wrote: I'm talking melting plastic hot!!! I'll try the polish trick my fuse is held in tight so I know its not loose
I know (see pic). That's why I asked about the wattage of the H4 bulb.Ed
Attachment BurntConnector.jpg not found
hey Ed...did your main 20 amp fuse have any problems during this problems.
Please Log in or Create an account to join the conversation.
- built408
-
Topic Author
- Offline
- User
-
Registered
- Posts: 56
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 20:15
The bulb Is a Philips h4 12v 60/55w.
1978 KZ1000 A2A with MKII body you know you like it
Please Log in or Create an account to join the conversation.
- built408
-
Topic Author
- Offline
- User
-
Registered
- Posts: 56
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 22:27
?
1978 KZ1000 A2A with MKII body you know you like it
Please Log in or Create an account to join the conversation.
- 650ed
-
- Offline
- User
-
Registered
- Posts: 15333
- Thanks: 2833
Re: Hot fuse problem.
17 Oct 2012 22:344TheKZ1000 wrote:650ed wrote:built408 wrote: I'm talking melting plastic hot!!! I'll try the polish trick my fuse is held in tight so I know its not loose
I know (see pic). That's why I asked about the wattage of the H4 bulb.Ed
hey Ed...did your main 20 amp fuse have any problems during this problems.
Believe it or not, no; it never did blow a fuse. I had been using an off-road only 100w (high beam) H4 bulb that lit up the night like an aircraft landing light. It worked great, but the bulbs only lasted a season or so before blowing; I think due to vibration? I gave up on them and switched to a normal wattage bulb without knowing about the overheated connector. I found the burned connector when doing some other maintenance on the bike. The connector actually still worked fine but clearly things were getting pretty hot using the 100w bulbs. I replaced the connector with an identical one. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
The following user(s) said Thank You: 4TheKZ1000
Please Log in or Create an account to join the conversation.
- 4TheKZ1000
-
- User
-
Public
- Thanks: 0
Re: Hot fuse problem.
17 Oct 2012 22:39
ya, im tring to help Paul with this problem....the only two items that share the headlight and main fuse I think is the ign switch? could this be the problem with main 20amp fuse getting really hot when headlight is turned on with key in on position?
thanks for help
thanks for help
Please Log in or Create an account to join the conversation.
- Motor Head
-
- Offline
- User
-
Registered
- FIX UP YOUR BIKE RIGHT AND CHEAP
- Posts: 5137
- Thanks: 393
Re: Hot fuse problem.
17 Oct 2012 22:47
Basically everything except for the starter motor, and the charging system goes through the Main Fuse. So the starter solenoid, tail/ brake lights, Ignition, fuel gauge if it has one or the light, gauge lamps, head light, etc. so if the main is getting Hot, when the headlamp is turned on, that is from the increased load. But most likely from poor contacts as mentioned already, at the fuse panel most likely. That slight increase in wattage at your headlight shouldn't be adversely effecting the fuse temp. Poor contact is resistance which makes heat. The head light bulb is a resistor, using resistance to make light.
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
The following user(s) said Thank You: 4TheKZ1000, built408
Please Log in or Create an account to join the conversation.
Moderators: Street Fighter LTD