Electrical conundrum revealed !

[DrBunsen]

Hi Everyone,

First time poster, long time lurker

I just wanted to share a life lesson I recently experienced, hoping that I will be the only one to make this mistake.

I'll keep it short and sweet.

I own a 1981 GS 650GL. Recently purchased from a great previous owner who re-built the bike about 3000km ago. We're talking everything.

- All chrome refinished and polished
- Electrical wires cleaned up or rewired
- Complete motor rebuild
- Complete stock exhaust rebuild

It runs like a dream. Perfect in every way, except some clutch slipping at about 7500 RPM. But I dont ride that hard, so not a huge issue.

I was riding it home a week ago, and ALL the running lights go out. Im thinking, not a huge deal, must be a fuse, right?

So FIRST thing I do is check the fuse. Looks good. No, I say, I'm not gonna do it half-assed. I pull out the multi-meter, and check for continuity across both endcaps of the 'lights' fuse. It's GOOD.

Now we have a problem. I start talking the tank off, and slowly but surely, spend the next 12 hrs spread over a week checking continuity across all the possibly affected wires. I am going crazy, they are all good.

I go to CliFFBase's website, I find the wiring diagram. Nothing makes sense. The ONLY thing that connects all the running lights is that fuse.

I check it with the multimeter again. Still good.

Then I actually take it out. And the end caps twists off.

Replaced it. Everything works. OMG, thats 12 hrs I am never getting back..

TL DR;

Fuse was good enough to pass continuity, but not the power needed to function.

Hope people read this and learn from me. Take the damn fuse out and replace it, just to be sure !!

[posplayr]

Hi Everyone,

First time poster, long time lurker

I just wanted to share a life lesson I recently experienced, hoping that I will be the only one to make this mistake.

I'll keep it short and sweet.

I own a 1981 GS 650GL. Recently purchased from a great previous owner who re-built the bike about 3000km ago. We're talking everything.

- All chrome refinished and polished
- Electrical wires cleaned up or rewired
- Complete motor rebuild
- Complete stock exhaust rebuild

It runs like a dream. Perfect in every way, except some clutch slipping at about 7500 RPM. But I dont ride that hard, so not a huge issue.

I was riding it home a week ago, and ALL the running lights go out. Im thinking, not a huge deal, must be a fuse, right?

So FIRST thing I do is check the fuse. Looks good. No, I say, I'm not gonna do it half-assed. I pull out the multi-meter, and check for continuity across both endcaps of the 'lights' fuse. It's GOOD.

Now we have a problem. I start talking the tank off, and slowly but surely, spend the next 12 hrs spread over a week checking continuity across all the possibly affected wires. I am going crazy, they are all good.

I go to CliFFBase's website, I find the wiring diagram. Nothing makes sense. The ONLY thing that connects all the running lights is that fuse.

I check it with the multimeter again. Still good.

Then I actually take it out. And the end caps twists off.

Replaced it. Everything works. OMG, thats 12 hrs I am never getting back..

TL DR;

Fuse was good enough to pass continuity, but not the power needed to function.

Hope people read this and learn from me. Take the damn fuse out and replace it, just to be sure !!

A continuity test is confirmatory but not conclusive as the ohm meter current/voltage seldom puts the same load on the circuit as proper operation.

Lessons learned are not soon forgotten , but unfortunately seldom do others learn from your experiences. Without doing a mathematical description, I'm sure you can now understand my comment re:confirmatory v.s. conclusive while others will just breeze right past.

[tkent02]

Change to the modern blade type fuses and you won't have to do this again.

[RichDesmond]

...Fuse was good enough to pass continuity, but not the power needed to function...

Yep, I've had that happen a couple of time over the years, including on an 850G.

I never even bother with the continuity check any more, if I suspect a fuse I just replace it.

[barnbiketom]

if you checked the fuse WHILE IT WAS INSTALLED, it may have read continuity, thru the circuits on the bike no doubt.
when checking ohms, ALWAYS isolate the part you are checking ...

[RichDesmond]

Change to the modern blade type fuses and you won't have to do this again.

I've had the "looks good/tests good/isn't good" on those too. (Just once though that I can remember.)

[tom203]

DrBunsen said...." It runs like a dream. Perfect in every way, except some clutch slipping at about 7500 RPM. But I dont ride that hard, so not a huge issue"

Check that correct oil was used or else! how many miles led to this rebuild??

[DrBunsen]

It was rebuilt 37,000 km in to it's life.

[DrBunsen]

Change to the modern blade type fuses and you won't have to do this again.

Yeah. I think that may be my next project. Turns out, the headlight is a H4, which I think is an upgrade, which in turn might explain the lights fuse blowing once in a while. I wish they made a 11amp fuse !

[Steve]

Yeah. I think that may be my next project. Turns out, the headlight is a H4, which I think is an upgrade, which in turn might explain the lights fuse blowing once in a while. I wish they made a 11amp fuse !

The H4 headlight is stock, and even if it weren't, it would be draw the same amount of current as a sealed-beam light.


Now, back to the first post, ... would you mind translating "TL DR" for me?

I am one of the old fogies that is accustomed to ALL the keys on the keyboard being used.

.

[Nessism]

When restoring/refurbishing old GS bikes I always change the fuses for just that reason.

[Badooka]

Welcome and good point.
I wonder why the engineers that be never pondered circuit breakers for a motorcycle?

[Steve]

Welcome and good point.
I wonder why the engineers that be never pondered circuit breakers for a motorcycle?

You can second-guess them.

For glass fuses. Less than $3 each.



For blade-style fuses. Just under $3.25 each.


Can probably shop around a bit and find them cheaper, this was just the first place I found.

.

[cableguy]

The H4 headlight is stock, and even if it weren't, it would be draw the same amount of current as a sealed-beam light.


Now, back to the first post, ... would you mind translating "TL DR" for me?

I am one of the old fogies that is accustomed to ALL the keys on the keyboard being used.

.

TL DR = Too Long, Didn't Read
Not sure why he would put that in his own post though, it's mainly used in faster moving boards where one person goes on a long-winded rant and subsequent posters will qoute, then add TLDR as a way to lightly insult the ranter and remind him that he is not the end-all be-all of the forum, and that the best comment is a succinct one. You will probably not suffer that insult, due to your consistent succinctness(?)

[bwringer]

Change to the modern blade type fuses and you won't have to do this again.

Nope.

I've had the "looks good/tests good/isn't good" on those too. (Just once though that I can remember.)

Yep.



Many of us have been there done that, and gotten the greasy t-shirt to prove it. Never trust a fuse. Or a fuse box, for that matter.


I do like those circuit breakers, Steve... I had no idea those existed!