Need help from electrical gurus w/intermittent short blowing ignition fuse
I have been able to complete many diy projects and solve/repair a bunch problems on my m/c's and cars by searching
Google. I also have this posted on Ninja 250 org. forum. Most of my time is spent on the Adv forum.
But this one electrical problem w/my Ninja 250 has me totally stumped . I have read extensively about the problems that
could be cause of the #3 10a igniton fuse blowing. My son's 2004 Ninja 250 has an intermittent short that is causing #3
ignition fuse to blow. The first time it happened while on the hwy, lost power and had to be towed home. #3 fuse was blown.
Here is what has transpired so far;
1. Replaced fuse and turned on ignition, immediate pop.
2. Removed gas tank to look for obvious breaks in harness and connections, nothing found.
3. put new fuse in, good to go. Started up bike, tried pulling and twisting wires at obvious connections relating to #3 fuse, all
the safety switches, ignition, etc. Could not recreate the short.
4. Put the tank back on, tried starting, as soon as I turned the key, the fuse immediately popped.
5. Took the tank off was going to do ohms check on connections, but short went away.
6. Tried running the bike for about 30 minutes while on a stand, revving up rpms, thinking it might be heat related. Bike
7. Buttoned the bike back up. Took it for a spin, 10 miles from my house, blew the fuse, towed back home.
8. With the #3 fuse blown, was going to track the short by w/multimeter, had to take the tank off to get to the connections,
short disappears again.
9. I now have the harness pretty much apart and checking individual wires for any sort of fraying or pin holes. Have found
10. I took apart both bar end housings to check the kill switch and clutch switch wiring. Took the bottom cap off the ignition to
check wiring. Checked the wiring at kick stand switch and neutral light switch at engine. Everything looks good.
My friend thinks it might be coil related and t when it heats up while riding it might cause a short. I have blown the fuse while
the bike was cold after placing the tank back on, so I don't know about his theory. I pulled apart the junction box and all the
pins and solder points look good. Looking at the schematics , could a bad rectifier or ignition module cause a short to the
#3 fuse? How about the coil? By the description I provided, it seems to be that it is most likely a wire to ground causing a
major short. I have closely inspected the wires under the tank for even a small pinhole but nada. All the plastic connectors
are intact. I have traced the wires forward to dash and handle bars. The only thing I haven't traced are the wires running
from the junction box rearward as they are not connected to ignition fuse. Any ideas would be welcome. I am about to throw
in the towel and maybe buy complete new harness, but that might not even be my problem.
The big problem is that the bike is running fine right now so I can't use the meter to isolate the culprit.
Thanks for your time,