83 KZ1100 fuse

I keep blowing the 10A fuse in the fuse block under the seat labeled horn/ignition. I have done some wiring changes up behind the headlite to mount a fairing. When the fuse blows, I have no neutral lite, oil lite and the tacho don't work. I did not make any changes to the multiwire plug connectors up there, just single wire pull aparts for the lites. It doesn't blow all the time, and when it does it seems to happen when I'm getting on the power, running it kinda' hard. I thought I'd ask on here before I started digging around, see if it was a common occurance or if anyone had any input on the matter. I did get my top case mounted and out the crash bars on. Looks like a BIG bike now...

I just put a 15 A fuse in there. All is well.

I do not think all is well!

According to the wiring diagram the fuse you replaced was a 10amp fuse. Replacing a 10 amp fuse with a 15 amp fuse is a bad thing to do because the wiring in that 10 amp circuit would have been sized for 10 amps not 15 amps. From what you wrote it appears that the 10 amp fuse was blowing, and this indicates that a load greater than 10 amps is present on that 10 amp circuit. By blowing, the 10 amp fuse was protecting the wiring in that circuit from being overloaded. Replacing the 10 amp fuse with one of a higher rating means that overload is now being run through the wiring which presumably was sized for a max of 10 amps. Consequently, you now run the risk of overheating the wiring which not only could melt the insulation and cause a short circuit but could also result in a fire. Not a good idea!

I would urge you to reduce the load in that circuit and install the correct 10 amp fuse. To reduce the load you may simply want to add another circuit with its own fuse to provide power to anything you added when you made changes. Ed

Bad terminals and connections can increase current draw due to voltage drop, common on old bikes. A once over checking all connectors and grounding points and ensure you only ignition and horn circuits running that fuse - ie not had headlights wired in somwhere past the fusebox.

Maybe do some further investigation, like what current Amps you have going through the fuse and voltages.

A 15A fuse swap won't tell you where the problem is, most breakdowns are electrics.

Fuseboxes and ignition switches are known problem areas on these.

I went and got a different 10A fuse from a local auto parts store. The ones I was blowing were actually 9A fuses out of a combo pack I got at Autozone car parts store. That's all they had that short of length. The 10A I got in there now is actually shorter than the stock ones. We went for about a 65 mile ride the other day and it held up. If it blows again I will investigate further and figure it out.

One of the connectors that is hot with the key on, that hooks to one of the horns was dangling in the wind, making contact with the exhaust pipe once in awhile...I reattached it to the horn, hopefully no more blown fuses...

The auto parts stores around here don't have a very good selection of glass fuses, so I ended up getting them at Amazon.com.

1981 KZ650-CSR & other models:
AGX = 1" (25mm)(main fuse box)
AGC = 1-1/4" (30mm)(acc fuse box)

same situation here in western pa. i rode it to work today and didn't blow it, about 35 miles...and a friend came over ( a KZ owner from years gone by and he helped me put a bit of air in the forks and the rear, it sets up a bit and feels alot better...