Tale of a blown main fuse

I got about 2km - litte over a mile from home on Saturday and the bike just suddenly and totally died. I knew before I reached the curve that it was electrical since I had no turn signal and no neutral light after I found neutral that is. First thing to check was the battery connections which were fine so next on the list was the main fuse. Sure enough it was burned out. Luckily I had a packet of spares so I popped in a fresh one fired up and turned back toward home. Got about a third of the way and same thing. Put in a 25amp and it died as soon as I turned they key it the ignition. Put in a 30 amp which died immediately.
Started checing the wiring. The white and red wire from the battery terminal to the main fuse was in bad shape where it connected with the battery so I cut it back and reconnected. Did'nt expect it would make a difference and sure enough when I put in another 30 amp it blew right away. Checked the wiring harness under the tank and around the coils - seemed fine. Removed the headlight and took a look in behind and could'nt find anything which might be causing a short. So....the dilemma. Do I put a piece of metal across the fuse contacts, blast for home and risk letting the magic smoke out of some high priced component or do I push it ? Well, I ended up deciding to push the bike home. A heavy sucker but I think the shame and embarrasment of having to push was worse than the physical effort! Hope I never have to do that again. Sure dont want sme dude on a Harley forum joking about how he saw some guy pushing a UJM

Later I revisited the wiring jumble in the headlight shell and found a turn signal connection which had lost a bit of electrical tape (blame previous owner)and was the likely culprit. Spent a coupe of hours on Sunday repairing connections and inserting shrink wrap and while I was at it I upgraded to the blade style fuses. I could'nt find any more of the old glass ones.

Ah the joys of owning an older bike.

Post edited by: JR, at: 2007/09/03 21:05

Well it's good you both made it home safely.

I too have experienced the "Blown main fuse" fear when out on a ride. I blew a few on a ride, and worried what was causing it, or what's gonna fry?
I was lucky to find the short and ride on, after 3 or four fuses blown, with some distance traveled between each blow. :pinch:

When my main was inexplicably blowing, I found a short in my run-stop-run switch on the right hand switch cluster. The insulation under the rotary switch cover was deteriorating and allowing a short to the cluster housing.

Got a new switch cluster from Z-1 and all is well again. No drama. It all happened in my garage.

Had to keep riding, though. So while I was waiting for the new switch cluster, I took the old one apart and hard-wired the kill switch leads together.

I have a 1978 KZ650 SR. I replaced the handlebars, d/t not being the right type. Since then....I "pop" fuses. Is it possible that I just need to put tape on the handlebars under the controls? Or is there a secret wire that I may have overlooked? I am considering parting with the bike, but would perfer not.

Barry Follmann
618-727-0592
herrinfiretiger1@yahoo.com

Blowing or popping fuses is almost invariably caused by a short to ground (frame) and the only solution is to trace the wires and carefully examine for where the short is happening. Since you replaced the handlebars I would suggest you open the controls and look for a pinched wire or poor connection or missing insulation or something along those lines. Somewhere a bare wire is touching the frame where it should'nt.

The only way to do it is to do it right, no shortcuts or the problem will come back when you least expect it.

My 76 KZ900 was blowing the main fuse left and right until I replaced the horn! There was a bad ground wire but replacing that was not enough. The plastic casing by the connectors was cracked and the connection would move and short out.