Did I fry my Compufire?

[Guest]

Bought one of those little propane heaters on Craigslist a while back, so I figured I'd finally fire it up and spend some time out in the garage tonight. You know - clean up, organize stuff, and finally install that Compufire I bought a few months back.
Everything went fine until I was doing the final connections. I inadvertently attached both the ground wire and the positive wire from the Compufire to the positive battery terminal. When I went to attach the ground wire from the bike to the negative terminal of the battery, there was immediately smoke coming from the general area of the new R/R. I quickly removed the ground wire from the negative terminal, and soon realized my mistake.
I was either going to cry or pick up a sledge hammer, so I walked away for a bit.
Came back and attached the wires correctly. Bike started right up, but I did not have the time to run any of the stator paper checks. Did I most likely fry the Compufire? Anything in particular I should be aware of when I get out the volt meter tomorrow?

[tkent02]

Bike started right up, but I did not have the time to run any of the stator paper checks. Did I most likely fry the Compufire? Anything in particular I should be aware of when I get out the volt meter tomorrow?

Let us know how these tests come out.

[posplayr]

If you had the positive and negative R/R wires tied together then the short did not generate any current inside of the Compufire.

You should have blown a fuse though so not sure why you did not do that?? Check for burned/melted wires and replace as necessary.

[seano]

If you had the positive and negative R/R wires tied together then the short did not generate any current inside of the Compufire.

You should have blown a fuse though so not sure why you did not do that?? Check for burned/melted wires and replace as necessary.

The in-line fuse was not blown. I'll check the glass fuses in my fuse box tomorrow. Thanks!

[posplayr]

The in-line fuse was not blown. I'll check the glass fuses in my fuse box tomorrow. Thanks!

you probably smoked a ground wire; are you running a 40 amp fuse in the Compufire? You should change that 20-25amp if you are running the CF direct to the battery.

Drop it to 15 amp if you are running the stock configuration (which I assume you are not).

[seano]

you probably smoked a ground wire; are you running a 40 amp fuse in the Compufire? You should change that 20-25amp if you are running the CF direct to the battery.

Drop it to 15 amp if you are running the stock configuration (which I assume you are not).

Yes, 40 amp fuse in the Compufire. I'll swap it out and check my ground wires, thanks!

[OldVet66]

Your short was between the negative wire on the Compu-Fire and where the heat sink was grounded to it's mounting points on the bike. The ground wire is connected to the heat sink. You would have created too much sparking (like trying to connect "+" to "-") to hook it up and started smoking the 10 gauge ground wire's insulation if it had been a dead short so what you are mounted to is not well grounded to the bike at all. That probably saved you this time, but is a good argument for running a common ground to eliminate poor grounds throughout the electrical system.

[seano]

Your short was between the negative wire on the Compu-Fire and where the heat sink was grounded to it's mounting points on the bike. The ground wire is connected to the heat sink. You would have created too much sparking (like trying to connect "+" to "-") to hook it up and started smoking the 10 gauge ground wire's insulation if it had been a dead short so what you are mounted to is not well grounded to the bike at all. That probably saved you this time, but is a good argument for running a common ground to eliminate poor grounds throughout the electrical system.

You're talking to an electrical dummy here. It's all greek to me

[posplayr]

Your short was between the negative wire on the Compu-Fire and where the heat sink was grounded to it's mounting points on the bike. The ground wire is connected to the heat sink. You would have created too much sparking (like trying to connect "+" to "-") to hook it up and started smoking the 10 gauge ground wire's insulation if it had been a dead short so what you are mounted to is not well grounded to the bike at all. That probably saved you this time, but is a good argument for running a common ground to eliminate poor grounds throughout the electrical system.

You are probably correct. He had a poor ground but probably fried either the R/R (-) lead inadvertently connected to the battery or a B/W going from harness to the R/R (-). (see attached figure).

Ground wires are probably toast and more than likely the relatively long length B/W in the harness. Since the CF R/R(-) is tied directly to a heat sink, he probably burned the B/W in the harness instead resulting in a lot of smoke.

Since the R/R(+) and the R/R(-) are tied together even if at the positive lead of the battery if is probably not possible to get current to flow through the R/R (i.e. in or out red and out /in black from the R/R) unless the bike were running and trying to charge. Since the only power was from the battery there is no way to create potential difference across the R/R leads to get current to flow through the R/R so it is safe.

[OldVet66]

Think of the negative wire of the Compu-Fire and the body of the Compu-Fire as a single wire that you hooked from battery positive to where you mounted the Compu-Fire. It would have started welding the positive terminal of the battery and sparking all over the place if the part you mounted the Compu-Fire to had a good ground back to the negative side of your battery. It obviously did not, or you would have known something was drastically wrong. All the metal parts of the frame and associated mounting plates should be solidly connected back to the main black ground wire that goes from your battery to the transmission housing of the motor. Corrosion and rust gets between the parts bolted together and starts to partially insulate them, so that connection back to the battery is no longer good anymore and requires a lot more current to complete the circuit. In this case it worked to your advantage by not causing any appreciable damage. The frame was used as the return to the battery for all circuits in your electrical system, so it is important for it to work that way so it doesn't start pulling more current than originally designed trying to complete these circuits. A bike thirty some odd years old needs all the metal parts torn down and cleaned like new where they bolt together, or more practically run new grounds to a central point on the bike and spider out to the frame parts doing an end run around all the old corrosion and rust.

[posplayr]

Think of the negative wire of the Compu-Fire and the body of the Compu-Fire as a single wire that you hooked from battery positive to where you mounted the Compu-Fire. It would have started welding the positive terminal of the battery and sparking all over the place if the part you mounted the Compu-Fire to had a good ground back to the negative side of your battery. It obviously did not, or you would have known something was drastically wrong. All the metal parts of the frame and associated mounting plates should be solidly connected back to the main black ground wire that goes from your battery to the transmission housing of the motor. Corrosion and rust gets between the parts bolted together and starts to partially insulate them, so that connection back to the battery is no longer good anymore and requires a lot more current to complete the circuit. In this case it worked to your advantage by not causing any appreciable damage. The frame was used as the return to the battery for all circuits in your electrical system, so it is important for it to work that way so it doesn't start pulling more current than originally designed trying to complete these circuits. A bike thirty some odd years old needs all the metal parts torn down and cleaned like new where they bolt together, or more practically run new grounds to a central point on the bike and spider out to the frame parts doing an end run around all the old corrosion and rust.

We have to see but my bet is the B/W in the harness is smoked.

[OldVet66]

That is very possible depending on how long it took to disconnect the battery. Those small ground wires would have heated up pretty quick and would warrant some investigation, but since the initial hook up didn't scare him half to death, he might have been lucky and just burnt some insulation near the high contact resistance points. He should cut far enough into the cable bundle near the solenoid ground to see how far the damage may go. It would have taken a little while to heat up the entire ground circuit enough to melt all the insulation, but anythings possible.

[seano]

I've not come across any melted insulation on any of the wires thus far. I will be sure to check the B/W wire in the harness though.
Although I really don't know squat about electric stuff, I did spend quite a bit of time cleaning up the big transmission ground wire a while back, along with replacing a bunch of the bullet connecters throughout the bike using dielectric grease, etc.
I just bolted the CF to the bottom of the battery box - didn't remove any of the rust . Think I should just yank it back out and hit it w/ a wire wheel?
Thanks again for all your help. I'm going back out to the garage and will report back

[OldVet66]

Better still, pick a convenient place for a central grounding point. It could be anywhere on the bike as long as a wire from the negative post of the battery is of a large enough gauge. Preferably 8 gauge from the battery and in a place where you could stack multiple ground wires. Run from there to one of the mounting bolts on the Compu-Fire with a 10 gauge wire. Later you can decide other places on the bike that might need a clean ground. The battery box is famous for loosing its ground. I use stainless steel bolts and nylon insert locking nuts with a flat washer on the bolt and nut side and star washers on the ring connector side to dig in and insure a better ground. I think you are lucky you mounted it to the battery box.

[seano]

Better still, pick a convenient place for a central grounding point. It could be anywhere on the bike as long as a wire from the negative post of the battery is of a large enough gauge. Preferably 8 gauge from the battery and in a place where you could stack multiple ground wires. Run from there to one of the mounting bolts on the Compu-Fire with a 10 gauge wire. Later you can decide other places on the bike that might need a clean ground. The battery box is famous for loosing its ground. I use stainless steel bolts and nylon insert locking nuts with a flat washer on the bolt and nut side and star washers on the ring connector side to dig in and insure a better ground. I think you are lucky you mounted it to the battery box.

Ok, no smoked B/W wires - there are 2 of them that go to the negative terminal, along w/ the large (8 or 10 gage) ground wire to the trans. No smoked wires anywhere - took the battery box & CF out and had a thorough look. Did the Stator Paper Quick Test (no headlight) and got 12.8V w/ key off, 12.13V w/ key on for 10 seconds, 14.4V at 1,500 rpm, 14.36V at 2,500 rpm, 14.36V again at 5,000 rpm, and 13.25V w/ key off.
The transmission ground looks like a good place to for me to run a 10 gage ground wire from one of the CF mounting bolts. So, I'll now have this new ground as well as the other ground from the CF to the battery neg. Will this now have sufficient grounding? The way the CF is mounted to the battery box, there's not a whole lot of surface area between the 2 surfaces. I'd prefer to leave it this way unless it's really necessary.