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Discussion Starter · #1 ·
So, I have a dead fuse and the taillight and dashlights are out - I'm at work with no equipment but what's in the tool kit (although I can prolly get some tape). Is there a common place for an '81 CX500c to short?
 

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O.K., given that you're at work this is going to be iffy. How many spare fuses have you got?

How long did the last fuse you put in last? I'm assuming you got to work on the last one. Maybe another would get you home.



Either way,

I'd flex the loom in various places [particularly around the headstock] and see if you can induce the fuse to blow to try to pinpoint the problem area and then expose the wires and try to find it visually.



A look in the headlight shell and at the tail light itself wouldn't hurt either.
 

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Discussion Starter · #5 ·
It lasted less than a minute - I'm thinking it probably is somewhere that flexure causes a short to the frame. Just thought perhaps this model has a common point : "oh, yeah - they all eventually break right at X".



I don't think the one spare fuse will even get me down the block, so I hope this short will be easy to find.
 

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A common point for this sort of fault is around the headstock.



Put the bike on the centrestand and turn the steering lock to lock and check where the main points of flex are and any possible chafing on the harness where it rubs against the frame etc..



Good luck.
 

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Something similar happened to me and I changed my 7V regulator and it did the trick. There are several DIY kits on this forum or you can buy a pre-assembled one here. Just make sure the connectors match to your current regulator.
 

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Discussion Starter · #9 ·
Started work - took out the bad fuse, put in the new one, and it worked with swiveling the handlebars. Turned it around, and as soon as I moved it to the road, the fuse popped. Now they pop consistently, so it's not intermittent. Removed the seat and tank, looked at the full harness- nothing obvious.

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And now it's pouring down rain and lightning in my driveway.

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Hmph.
 

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Discussion Starter · #12 ·
Put a light across the blown fuse - it stays lit while I rattle the wiring harness until I hit it near the headlight (flickers). Maybe in the headlight/connection box... It was too hot to continue - hope I can get to it tonight.
 

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Put a light across the blown fuse - it stays lit while I rattle the wiring harness until I hit it near the headlight (flickers). Maybe in the headlight/connection box... It was too hot to continue - hope I can get to it tonight.
Now you're thinking, fuses are expensive, a test light is not. So many wire crammed so tightly inthe area you're dealing with won't make it easy but now that it's leaning towards the dead short side it shouldn't be hard to pinpoint.
 

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Maybe you can use an Infrared gun to look for temperature irregularities/high temp = short/bad connection? just an idea if you can borrow one. You can certainly check your fuse blocks to see if on side is hotter than the other?
 

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Discussion Starter · #15 ·
Maybe you can use an Infrared gun to look for temperature irregularities/high temp = short/bad connection? just an idea if you can borrow one. You can certainly check your fuse blocks to see if on side is hotter than the other?


Thanks, but I'm still living in the '50s...
 

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Discussion Starter · #16 ·
Fiddled with it Saturday until the light didn't work - now I can't get it to fail. There's nothing quite like trying to troubleshoot intermittent, eh?

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At least now it works.
 
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