No capacitor, more blown fuses?

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Jun 14, 2007
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Yes, I'm capacitor obsessed this evening - please bear with me!

Anyway, my Commando's been blowing main fuses lately. I have to do a short check, or maybe replace the whole dinged harness, but that's for winter. I thought the capacitor might be the problem - 34 years old, and when removed, had the telltale "dimple" - but a screwdriver across the terminals produced a spark, and since removing it, the interval between blown fuses is far less - I used to at least get a few miles, now a quarter mile, tops.

Any suggestions welcome as always. Thanks folks - BrianK
Try this: here is tip for electrics per John Healy :

replace the fuse with a small light bulb. begin to disconnect one item at a time, headlight, tailight, etc.....when the bulb goes out, you found your short. Repair short and replace fuse....
Thanks Norbsa - that's an interesting method. How does that work? (I'm an electrical complete newbie, but trying to learn theory along with practice.)

I did invest (not much - cheap New Englander here!) in a "short finder" - the "buy it don't make it" equivalent of a self-resetting circuit breaker and a compass you run along suspected wires - but shorts ain't easy, as I understand it, and it'll be a long winter.....

Thanks as always for your help - B
Okay, I think I get it - connecting across the fused HOT wire, the light is on if grounded - meaning shorted out so volts can get home to papa earth somewhere. When you disconnect the shorted circuit, the circuit is broken and the light goes out.

Which means this works even with power "off" in switched circuits?
Power leaves the battery as potential is presented. It returns via the frame and grounding wires to the battery. A short by definition is a place were a power wire is making unwanted connection with the frame or a grounding wire. When you use a light bulb instead of a fuse it can't light up unless there is potential. If there is no power coming back to ground on the battery there is no light your fixed.
Thanks Norbsa. I appreciate the help (and will surely abuse the privilege in the future....). Cheers - BrianK
Hey, if I stuck an ammeter's probes into the fuse receptacles, wouldn't I see some current draw so long as there was a short (similar to the lamp being lit), so that I could disconnect circuits and know where the short was when the ammeter stopped showing current? I.e., same principle/method, different tool?
A bulb can show you much less than an AMP gage likewise a volt meter even less. An ohm meter even less... and on and on.
Amp meter used in this location are very useful for checking the whole system as it's running with lights on to make sure there an AMP left for the battery to charging.
I'm sorry, does that mean a volt meter is better for this particular usage, and an ohmmeter still better? But wouldn't a volt meter show no voltage drop across the fuse connections regardless? And an ohmmeter would only show continuity across the fuse (and minimal impedance, presumably)? )(I'm guessing you assumed a greater degree of sophistication on my part - (i.e., it is assumed that you move the probes to other locations to do these tests) but unfortunately, I lack that sophistication...

I'm sorry, I'm lost. (and a few pints ahead of ya, so probably off to bed soon but will pick up this thread in the morning).

Despite my thick skull, I assure you I do appreciate your efforts to impart some wisdom to the small quantity of actual grey matter inside!

Best - Brian K
As a 17 year old I was having a similar intermittent problem and ran out of fuses miles from home. While sitting on the road side feeling sorry for myself I spotted a pencil in the gutter. I cut it to length and popped it in the fuse holder. The bike started first kick and off I set home. After a while smoke started billowing out of the side panel just as I'd used the rear brake. Problem found and solved. Wouldn't recommend it though. :roll:
Ah cash, the bodges of youth!

I thought I was through with them, being now a middle-aged yuppie biker (not a come-lately, though, pushing 30 years since that first Suzuki GT 380 (and I still carry spare sparklers on account of it!)

Still, out with the wife a couple weeks ago. She has a new Bonnie, which she'd been enjoying but which was a bit tall for her. She toppled it at a light and snapped off the gearshift peg. Whipped out a small vice grips (I was on the Snorter, and carrying enough tools to drop the engine and replace a bearing or two), clamped it horizontally on the gearshift lever (thank god it was the peg - $12 - and not the lever - $118!, as I subsequently learned), and god bless if she didn't have a perfectly workable shifter.

The wife looked at me as though I were not the ten-thumbed clod she hears turning the atmosphere blue in the garage on a regular basis (my motto is, "Tighten it until it strips then back off 1/4.") I suppressed my own surprise and we rode home. Bought a bolt of the proper size, wrapped it in duct tape, and we sauntered forth again.

Not rocket science, but danged if I didn't feel like I was 17 again myself, riding around on a wing and a prayer, duct tape and baling wire!
PS, I am not cruel, when we got home I also raised the fork tubes in the triple clamps. She can now almost flat foot it at stops. And I did invest in a new gearshift bolt/rubber. What a sport, eh!
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