Originally Posted by Seth S
I had an interesting problem a couple years ago on my 690. I was on a long solo trail ride and I was going down a long hill and at some point I stabbed the front brake the and bike stalled. I hit the start button and the bike cranked but didn't fire. Because it was a fuel injected bike I decided nothing could be done and that bike is now sitting at the bottom of a ravine here in Vermont.
Acutally I wiggled the ignition switch...cycled the switch on and off and noticed that the instrument cluster didnt do anything. Then I popped the seat off and checked the fuses...found the injection/cluster fuse was blown and I had 2 spares...replaced the fuse and fired back up...rode 100 feet...hit the front brake again and blew another fuse
. I then coasted down the mountain until i rolled out to the highway. I inserted my last fuse and realized the one connecting factor was something around the front brake. So I rode home and didn't touch the front brake. When I got home I could not duplicate the problem. I looked through the wiring harness and found some cracked wires in the front loom...repaired those and figured that was it. A week later I went for another ride and about 20 miles from home I had the same problem. replaced my fuse, turned around, and rode home...avoiding front brake.
So fuses blow because they overload on current...when you short 2 wires together your current goes infinite...hence blown fuse...so somewhere I figured there was a short. It only happened when I applied the front brake hard and the bike dove down in front. So I started inspecting any and all components in the front end that were affected by break dive...it took some time but I finally found a spot where the insulation on the speedo sensor cable had abraded against a metal fitting on the brake line and revealed the 3 wires inside. There is a power, ground, and sensor wire inside the sheath and as luck would have it the power wire had rubbed through. Every once in a while under hard front braking the power wire would rub against the fitting on the stainless front brake line which would short out the sensor through the instrument cluster and blow the fuse....which also killed the bike because the injection was on the same fuse.
I had a similar issue with a 1959 Ducati 175cc. Pulled the clutch in...giant backfire...launched the muffler tip about 100 yards...and died. After several of these episodes, I pulled the gas tank and found that the clutch cable was pushing the coil wire against the frame and grounding thru a bare spot on the wire..