1 [SOLVED!] Fuse #1 blowing shortly after ignition on/engine on, then doesn't do it after replaced and re-started Thu Aug 09, 2018 3:31 pm
boostd4
Silver member
[SOLVED! See post 21]
Looking for any electrical guru insight.
I'm continuing my diagnosis started in this thread:
https://www.k100-forum.com/t12767-sudden-no-start-with-starter-button-where-to-check-next
But symptoms have changed a bit and was looking to maybe get some new eyes on the issue.
As it sits right now, my 85 K100RS will blow the #1 fuse every time I start it after it's sat after running. Sometimes it will do it when I put the key on, then turn the choke on (fuse pops before engine starts). Sometimes it will do it a few seconds after I put the key on without touching anything. And sometimes it will let me start the engine, it will run for sometimes a few seconds, sometimes it will go about a block of riding before popping the #1 fuse. Engine still runs and all, just functions tied to that fuse stop working (most importantly brake lights that keeps me from riding it anyway).
A month ago, it was doing this completely randomly (not just shortly after startup). I pulled the tank and hooked a headlight bulb in line with the #1 fuse and jiggled wires until I found what I think was the clutch switch connector on the left tray under the tank would pop the fuse whenever I jiggled it. I cut it out and wired it straight and it stopped blowing the fuse for a few days until the above current scenario.
Link to connector I eliminated that would pop the fuse when I tapped it:
So why don't I just continue using the headlight bulb and find the short? Here's the weird part - After it blows the fuse, I can replace that fuse and it will start and run normally - FOR AS LONG AS I RIDE IT... whether that be 5 minutes or an hour. I've tried working every component while riding and nothing blows the fuse. If I shut the bike off and let it sit for at least 10 minutes, it will blow the fuse on restart (in the above ways). Then it works just fine after replacing the fuse.
The same goes for the Headlight bulb trick. When I pull the tank and hook the headlight bulb up to the #1 fuse, it glows bright (indicating there is a short) for about 1 second, then it goes out (no short present), and stays out until I actually RIDE THE BIKE for a while, then let it sit again.
So strange!
Any thoughts?
Looking for any electrical guru insight.
I'm continuing my diagnosis started in this thread:
https://www.k100-forum.com/t12767-sudden-no-start-with-starter-button-where-to-check-next
But symptoms have changed a bit and was looking to maybe get some new eyes on the issue.
As it sits right now, my 85 K100RS will blow the #1 fuse every time I start it after it's sat after running. Sometimes it will do it when I put the key on, then turn the choke on (fuse pops before engine starts). Sometimes it will do it a few seconds after I put the key on without touching anything. And sometimes it will let me start the engine, it will run for sometimes a few seconds, sometimes it will go about a block of riding before popping the #1 fuse. Engine still runs and all, just functions tied to that fuse stop working (most importantly brake lights that keeps me from riding it anyway).
A month ago, it was doing this completely randomly (not just shortly after startup). I pulled the tank and hooked a headlight bulb in line with the #1 fuse and jiggled wires until I found what I think was the clutch switch connector on the left tray under the tank would pop the fuse whenever I jiggled it. I cut it out and wired it straight and it stopped blowing the fuse for a few days until the above current scenario.
Link to connector I eliminated that would pop the fuse when I tapped it:
So why don't I just continue using the headlight bulb and find the short? Here's the weird part - After it blows the fuse, I can replace that fuse and it will start and run normally - FOR AS LONG AS I RIDE IT... whether that be 5 minutes or an hour. I've tried working every component while riding and nothing blows the fuse. If I shut the bike off and let it sit for at least 10 minutes, it will blow the fuse on restart (in the above ways). Then it works just fine after replacing the fuse.
The same goes for the Headlight bulb trick. When I pull the tank and hook the headlight bulb up to the #1 fuse, it glows bright (indicating there is a short) for about 1 second, then it goes out (no short present), and stays out until I actually RIDE THE BIKE for a while, then let it sit again.
So strange!
Any thoughts?
Last edited by boostd4 on Tue Aug 14, 2018 9:23 pm; edited 2 times in total