Blowing 30 Amp fuse trouble shooting in progress

[Rickrod3]

Hi all:

As per thread search recommendations, I checked the connector for the stator coil. I ashamed to say it was toast. So I replaced the connector. I tested the voltage output @ 2000 RPM =14.57 Volts. Took the bike for a couple of test runs. The time it took for the fuse to blow was definitely seemed longer but; much to my dismay right as I was duck walking the bike into the garage, XS11 Black out.

I checked my work and found one of my crimps on the stator wires was not good. (I'm hoping this was the cause.)

Back to the thread search:
I read a member had a problem with a grounded stator. So i checked stator and field coil. No conductivity to ground.
Stator across all three .5 OHMS Factory spec. is .4 plus minus 10 %
could this be the problem?

Field coil is the 3.5 Ohms.

Your thoughts please.
Thanks in advance.

[Barbarosa]

Just had my alternator/stator off today. Field coil, measured brown to green, is 3.5 ohms and the alternator, yellows to each other, is .5 ohms. Sounds like they tested good but maybe you just got it backwards lol. . The wiring diagram I use doesn't show the field coil as a separate connector from the alternator but my 1980 sg has a connector for each.

[Barbarosa]

Just had my alternator/stator off today. Field coil, measured brown to green, is 3.5 ohms and the alternator, yellows to each other, is .5 ohms. Sounds like they tested good but maybe you just got it backwards lol. . The wiring diagram I use doesn't show the field coil as a separate connector from the alternator but my 1980 sg has a connector for each.

Should have said WHITE wires. I get mixed up sometimes and forget what spins around and gets spun around too

[XJOK2PLAY]

Rickrod3,
Unfortunately, as these bikes are aging, the wiring harnesses are beginning to fail, too.

I just went through the similar problem with Bohn's '80 Special.
During the Colorado Rally, he experienced a similar meltdown.
He had replaced his connector, had a Geezer Reg/Rec, and his bike is one of the cleanest, nicest, best cared for 11's around. His electrical system had serious ghosts... some we could never pin point as the cause.

We found a known, great condition complete electrical system from a donor bike, went through thoroughly cleaning every connection, replaced the stator, field coil, reg/rec, lighting ballast... Everything. Works great now, and hopefully will be his last electrical issue for a long time.

I've been trying to find out what could be the culprit causing those connectors to fry. I have a theory, but nothing proven yet.

If you still have the glass 30 amp main fuse, you need to cut that garbage out, and update to an ATC type fuse. If your fusebox is the old glass type fuses, you need to swap that out, too. TC may still have some, and can get you the insulated 90 degree female connectors for it.

The reg/rec connectors are another area that gets corrosion, and can cause you charging issues.

RDMCGUY (Joe) Had a problem with his blowing the 30 amp main fuse on the Rally ride... turned out the hot post of his 12V flasher was shorting to the frame, blowing the main fuse. Easy fix.

So, ya never know where it is, but if you're blowing that 30 amp main fuse, it's probably due to a dead short somewhere. Do not bypass that fuse either! I've seen it done before... Doesn't end well... (unless you wanna use your bike to roast marshmallows...)

I'm curious- is your reg/rec a stock unit, or a Geezer unit?
Have you added additional loads to your bike's electrical system, like driving lights, air horn, or other accessory loads?
Have you ever gone through all the connections and cleaned them, and if so, used large amounts of dielectric grease?

Any info you can provide may help me get to the bottom of these meltdowns.

My guess- additional electrical loads have been added.
Dirty connections.
Old fuses / fusebox.
Stock connectors not rated for more than 20 amps, and should have been heavier duty for riding times lasting more than 2 hours.
Add in the age of these bikes...
Bob

[Rickrod3]

Bike History

I've had the bike since fall of 09. First thing I did was to replace the fuse box. I did use a radio shack glass fuse type replacement. It appears to be in good condition.

Stock Regulator. I did go through the connectors for what that's worth. thats why i was surprised to see the alternator connecter fried.

As to additonal loads none that are permanent. I do run a Garmin GPS and heated gloves in cold weather but those are fused and currently not being used and fuse as blown.
I also have a 1 volt drop through the ignition switch but that has been that way a long time even after I cleaned the switch contacts. I'm thinking of addressing that too since it will help the turn signals work better when idling.

Looking at the picture maybe I should change that pop rivet by the 30 amp fuse it does look too big. That too has been that way since 09.

I rode the bike about 8 miles yesterday and the fuse didn't blow. Armed with a pack of fuses, going to test ride it today a little further. It would be nice if it was solved or the problem gets worse (easier to find). If it happens again, I'm going to fit a fuse on the blue wire after the ignition switch. This will help me isolate if the problem is in the lighting circuit.

[Rickrod3]

Should have said WHITE wires. I get mixed up sometimes and forget what spins around and gets spun around too

Happens to the best of us.

Thanks

[Rickrod3]

Test Ride results so far

took a n 8 mile ride yesterday and an 18 mile ride this morning and so far so good. going to ride again after breakfast.

Starting to gain confidence. We will see

[Rickrod3]

30 Amp fuse blowing again

It happens while the bike is running, it blows I replace the fuse I can ride a few miles and it blows again. I previously replaced the stator connector, i checked it and it appears to be fine. I checked the stator coil got .4 ohms across all 3 wires. Checked the field coil and got 3.6.

I'm studying the wiring and as I understand it the 30 amp fuse feeds the auxiliary terminal, I guess it charges the battery since it connects to the red wire of the voltage regulator. Is there a way to check the voltage regulator to see if it is shorting to ground?

Additional steps I have taken:
I inspected the brown wire which also gets feed from the ignition switch.

Any thoughts or input would be greatly appreciated.

[TopCatGr58]

Hey Rick,

Scott/3Phase hopefully will chime in soon. XJOK2Play(Electrician) posted earlier and stated the most common obvious reason for the 30 amp fuse to blow is a direct SHORT of a power(12V+) to ground somewhere. But it's intermittent, otherwise it would blow as soon as you turned the key to ON. There are lots of places where the wires rub against the frame and can wear a raw to bare wire spot, but flexes due to handlebar turning, that keeps the bare wire away from the frame for a while, but then eventually touches and Poof, there goes the fuse.

I would first look over the harness where the wires are exposed especially around frame points, near the handlebars/steering neck, and even inside the headlight bucket looking for a worn bare spot. It's a real PITA to actually unwrap the harness, and it's less likely that it's worn thru a wire inside the wrapped portion.

The short is probably downstream from the fuse....in otherwords, I doubt if it's on the wires/side that are on the battery side, but on the harness side because it has to pull the current THRU the fuse for it to draw too much to overheat and blow the fuse. IF it was on the battery side, it would just spark/smoke and possibly catch the wire/bike on fire!

There are a few ways to help track it down when you can't easily see the bare wire. Using a Ohmmeter connected to the Harness Side of the 30amp fuse slot and to ground watching for it to go from open to showing Ohms=continuity=the short making contact could be difficult while trying to handle and maneuver the bike trying to wiggle the wires. Using a continuity test light that would only light up when you get continuity would be easier, but would need a small power supply again connected to the harness side of the fuse slot and to ground, and then when wiggling the handlebars, sitting the seat, etc, WHEN the short would occur, the light would come on which would be easier to see/detect. Good Hunting.

T.C.

[3Phase]

Rick,

Looking at the fuse block picture, you're working on your '79F and not the '80SG, correct? The '79F doesn't have the hazard flasher circuit so there's nothing there to worry about.

If the Main fuse keeps popping you might have a short in the tail light, the front running lights or one of the two unused accessory connectors in the headlight shell with a Red or Blue wire.

The '78E and '79F have dual element lamps for the front running lights and the tail lights. The lights are all fed by the same Blue wire that comes from the ignition switch and the 30A Main fuse, there is no separate Tail fuse until the 1980 and later models.


Another possibility is almost anywhere along the Red wire after the 30A Main fuse up to the ignition switch, including the 10A Aux connector block next to the fuse box.

After the ignition switch, you've already been into the Brown wire that runs down to the alternator, voltage regulator/rectifier, and the fuse block.

[XJOK2PLAY]

Hey Scott,
I remember back a couple years at the Canon City, Co rally, the group took off to ride up to Bishop's Castle, and after only a few miles Joe (RDMCGUY)'s 11 blew his 30 a main fuse and coasted to the side. We replaced it, after trying to search some of the wiring and not seeing a problem. A few miles later, it did it again. We tried to search some more, but couldn't find the short on the side of the road. So Joe missed out, and had his bike towed back to the campground. He later found it, under the seat area, back in behind the fusebox. IIRC, it was where the main wire, after leaving the fuse, was rubbing the frame...? Do you recall the specifics of what and where he found that short? Maybe Joe can chime in? Greg was one of us trying to help Joe that day, too. He was checking in the headlight bucket... I think it was like I said earlier, the flasher's post was touching the frame intermittantly, IIRC...

It might give Rickrod3 another idea of where/what to look for to find his problem.

I can't remember if Joe said it was due to something he had added to the harness or not...
JAT...
Bob

[Rickrod3]

Ok, thanks all. I'll keep digging I have a the fairing from a Venturer. I was suspect of the blue wire after the ignition switch. I'll pull the fairing and check I'll also try to find a good spot to add in a fuse on the blue wire after the ignition switch.

that might help localize the short and keep the bike running even with the short i'll only lose some lights till I can find it.

I added a Garmin GPS which has a fuse (never blown) that i have connected to the Aux terminal. I'm waiting on some flag terminals I'm going to get rid of the glass fuses. It is not the original. I'll put in the Atc type. When I do this I'll connect the GPS to the new fuse box.

[3Phase]

Rick,

The fairing wiring, lamp sockets, pigtail connectors and the pigtail are prime candidates for a short circuit.

There's nothing wrong with glass fuses, on my '80G I have the same Littelfuse fuse block from Radio Shack. If you trim the ends of the terminals where you soldered the wires and bend them 'in', you can use the stock "FUSE" cover too.

I use the space between the fuse block and the side cover to bungee a spare TCI on top of the fuse block. There's not enough room with the ATC fuse block so I'd have to find somewhere else to keep the spare TCI.


Bob,

Joe found the short when he burned his hand on the hazard flasher relay. He had a '79 but he'd put in an '80 or '81 wiring harness. The 'new' harness had the Hazard flasher circuit but the frame had no mounting tab under the seat for the flasher relay.

Eventually, the top center of the flasher relay got dented just enough to touch the hot pole inside the can but everything would be just ducky until the flasher bounced or rolled onto the seat pan or the frame, then it would pop the Main fuse.

Lather, replace fuse and repeat.

[skids]

Stock Regulator. I did go through the connectors for what that's worth. thats why i was surprised to see the alternator connecter fried.

Rick, the connector to the alternator can get fried because of arcing across a bad connection. It is not necessarily due to pulling too many amps. Did you say if you tested charging volts at say 3500 to 4000 rpms?

The running lights are a good place to check because of the way they run through the fender. I think there are other wires under the rear fender as well and I am not sure why they are there...perhaps provided for lighting on luggage?

[Rickrod3]

Rick,

Looking at the fuse block picture, you're working on your '79F and not the '80SG, correct? The '79F doesn't have the hazard flasher circuit so there's nothing there to worry about.

If the Main fuse keeps popping you might have a short in the tail light, the front running lights or one of the two unused accessory connectors in the headlight shell with a Red or Blue wire.

The '78E and '79F have dual element lamps for the front running lights and the tail lights. The lights are all fed by the same Blue wire that comes from the ignition switch and the 30A Main fuse, there is no separate Tail fuse until the 1980 and later models.

Another possibility is almost anywhere along the Red wire after the 30A Main fuse up to the ignition switch, including the 10A Aux connector block next to the fuse box.
Yes working on the 79F. Thanks for the info I'll keep inspecting for shorts. I'm thinking of adding a fuse block inside the fairing pocket. It seems that these bikes could have used a few more fuses.
After the ignition switch, you've already been into the Brown wire that runs down to the alternator, voltage regulator/rectifier, and the fuse block.

Yes working on the 79F. Thanks for the info I'll keep inspecting for shorts. I'm thinking of adding a fuse block inside the fairing pocket. It seems that these bikes could have used a few more fuses.