Electrical Problem - Blown Fuse

[herostar]

On Saturday night I was getting my bike ready for our local "Colorado Leaf Peeping Ride" and took it to gas up when it just stopped running. I lost all power, and immediately checked the main fuse. It was blown, but luckily I had an extra to get me home.

I've spent the last few days going over connections, checking grounds, making sure no wires are worn through and exposed. I can't figure it out! I've blown 5 fuses and want my next trip to buy more to be the last!

Are there any common electrical components, if broken, that would cause the main fuse to go out?

The bike runs fine, then just randomly blows fuses... I rode it to work 4 days last week then all of a sudden Sat. night the problem just started.

[posplayr]

On Saturday night I was getting my bike ready for our local "Colorado Leaf Peeping Ride" and took it to gas up when it just stopped running. I lost all power, and immediately checked the main fuse. It was blown, but luckily I had an extra to get me home.

I've spent the last few days going over connections, checking grounds, making sure no wires are worn through and exposed. I can't figure it out! I've blown 5 fuses and want my next trip to buy more to be the last!

Are there any common electrical components, if broken, that would cause the main fuse to go out?

The bike runs fine, then just randomly blows fuses... I rode it to work 4 days last week then all of a sudden Sat. night the problem just started.

not sure what it would be but just for some diagnosis ideas, this is what I would do.

remove all fuses except the main and see if the main still blows. If not then start adding fuses one at a time to see which one is causing the excessive current.

If it happening with engine on or off?

If it is still blowing then remove the R/R (all 5 wires) and try again.

You are going to have to do soem trial and error. Also would not hurt to pull the gas tank and look for pinched wires.

[Flaming Chainsaws]

I'm not sure if the "E" models are different compared to the "L" model but on mine, I have only one 15 amp fuse. There must be a short somehwere Maybe from all the vibration while riding, a frayed wire touches the frame?

[herostar]

There is only one main fuse. 15A.

After the first blown fuse I rode ~15 miles with no problems during a shake-down ride after checking connections... When I got home I parked the bike, still running, to open the garage door. As I pulled the bike into the garage the fuse blew again.

The next time it blew about 1 minute after starting and running, as I was backing it out of the garage.

The third time (after checking connections again...) it blew after I rode it 100 yards down the street.

So far it's only been when the engine is on. I'll give the R/R a check next I guess...

Any other ideas?

How bad of an idea is it to temporarily close the circuit (no fuse) to test voltages?

[DanTheMan]

[QUOTE=herostar;1290704]There is only one main fuse. 15A.

After the first blown fuse I rode ~15 miles with no problems during a shake-down ride after checking connections... When I got home I parked the bike, still running, to open the garage door. As I pulled the bike into the garage the fuse blew again.

The next time it blew about 1 minute after starting and running, as I was backing it out of the garage.

The third time (after checking connections again...) it blew after I rode it 100 yards down the street.

So far it's only been when the engine is on. I'll give the R/R a check next I guess...

Any other ideas?

How bad of an idea is it to temporarily close the circuit (no fuse) to test voltages?[/QUOTE=herostar;1290704]

Bad idea to bypass the fuse. One of our other members did that on his 450 and melted down the whole harness under the gas tank , here's the thread: http://www.thegsresources.com/_forum...d.php?t=165885 . Find the short!

[pete]

I'll second, no third, no fourth the suggestion to find the short.

From what you're describing, it's sounding like a 12v wire somewhere has probably been rubbing against something for years and has finally worn away enough insulation to short against the frame.

I've had this happen before and it's a complete PITA to find.

All I can suggest is pick either the headlight bucket or the tail and work backwards/forwards down the bike, checking everything.

One thing you can do which may make it easier to track down is start 'er up with a new fuse, then give the wiring loom a shake in one area and see if it blows. If not, move to another area. If so, you got it narrowed down to a smaller amount of loom

[herostar]

One thing you can do which may make it easier to track down is start 'er up with a new fuse, then give the wiring loom a shake in one area and see if it blows. If not, move to another area. If so, you got it narrowed down to a smaller amount of loom

I think this is going to be the plan, I just didn't have enough fuses to do it the other day .


In regards to running without a fuse... I saw somewhere that a person suggested hooking up a small light bulb like a turn signal where the fuse goes. They said that the bulb should be dim during normal operation, and will be bright when a short happens.

Does anyone think this will work or is it too dangerous for the rest of my electrics...???

[posplayr]

I think this is going to be the plan, I just didn't have enough fuses to do it the other day .


In regards to running without a fuse... I saw somewhere that a person suggested hooking up a small light bulb like a turn signal where the fuse goes. They said that the bulb should be dim during normal operation, and will be bright when a short happens.

Does anyone think this will work or is it too dangerous for the rest of my electrics...???

you could do the same thing with an ammeter; it is not telling you where the short is however.

[terrylee]

I'm the poor sorry member who melted his main harness by bypassing the one fuse to just get home. So do not do that!! Due to couple of great guys on here I figured out my problem. One thing I did do was switch to a harness with a fusebox and four places for fuses. I don't know how difficult it would be to do that with 450 harness, but it is a good idea. As you can see from my thread I had a problem with fuse blowing to lights after installing newer harness. I was glad I had the fusebox because it only blow the fuse to the lights and nothing else. Long story short(Ha!) do as was suggested to me and unplug everything but battery, ignition and fuse and start plugging things in one at time till fuse blows. Don't know if this would work since yours doesn't blow everytime, but it sure worked for me. Good luck, I thought I was going to loose my mind before I found my problem. terrylee

[bluewool]

Definitely a test light, unless you have an analogue ammeter.
I had the same problem, -twice- once it was the harness at the gear position indicator (I don't know if the 450 has one.) the second time it was the goofy brake lever switch.

[herostar]

I used an ammeter today and couldn't find the problem.

With the bike not running, but on, I turned on all the electrics I could (blinker, high beams, brake, gear shift) and it ran at a max of 11.7A.

When the bike is running the fuse is seeing about 18A. What would cause this much more current to run thru the fuse?

Also, my blinker isn't blinking for some reason.

[tom203]

I used an ammeter today and couldn't find the problem.

With the bike not running, but on, I turned on all the electrics I could (blinker, high beams, brake, gear shift) and it ran at a max of 11.7A.

When the bike is running the fuse is seeing about 18A. What would cause this much more current to run thru the fuse?

Also, my blinker isn't blinking for some reason.

Way back, posplayr said to unplug r/r. try this and then run bike- still 18 amp draw? If no, then r/r or stator wiring is suspect.

[posplayr]

Way back, posplayr said to unplug r/r. try this and then run bike- still 18 amp draw? If no, then r/r or stator wiring is suspect.

probably more the R/R is bad. The current typically peaks at about 14 amps at 2.5-3K RPM. If you are seeing more current than that then it it is more likely an internal short in the R/R causing it to pull current from the battery (blowing the fuse).

This really teh reason why there is a fuse between the battery and the R/R . Protect the harness if there is a short across the battery.

[tom203]

probably more the R/R is bad. The current typically peaks at about 14 amps at 2.5-3K RPM. If you are seeing more current than that then it it is more likely an internal short in the R/R causing it to pull current from the battery (blowing the fuse).

This really teh reason why there is a fuse between the battery and the R/R . Protect the harness if there is a short across the battery.

Yeah, when bike runs and the stator is sending juice to r/r, something is probably shorting internally- strange r/r doesn't trip fuse before it runs. weak diode? can block 12.5 volts, but not 14 volts.

[herostar]

Update:

So I got a little discouraged about a month ago because my 450 died two days before a local meet, then my new (to me) 750 died the next day. I was angry, so I didn't work on anything until this weekend as it's time to do some fall cleanup.

I did some tests and it turns out the '81 GS450E needs a new regulator/rectifier. It's a 5-wire unit.

Does anyone know where to get a good one for cheap?

Would it work if I scavenged the one from my '83 GS750E? (the engine seized, won't be riding any time soon...)