For the love of PAMCO Ignition systems help me figure out my electrical problem.

[JE4570]

Background info:

1979 xs650 special

Pamco unit with e advance and coil that pete sells with it.

So I received another pamco unit from pete after my first one fried so this time I put a 7.5 amp fuse in line with the coil from the power and changed the 10 amp fuse in my fuse box to a 7.5 amp one to protect it. Also cleaned every electrical connector I could find.

Well going down the road after installing the new one it quit on me only for me to find the 7.5 amp fuse in the fuse box had blown. (not the one I installed directly before the coil) I am not sure what I should do now. The pamco is still fine. (I tested it) I am just wondering if that fuse box fuse needs to be 10 amp? I am trying to be careful not to break the pamco. I had my friend rev for me whil i checked charging voltage an I got to ~14V at 4000 rpm.

My coil tested fine and I am using the one pete sells with his units.

I am wired correctly and I am using crimp on connectors so everything in that department looks good

My charging system is the stock kind except someone put in a reg/rec combo unit in it.

Where should I be looking next? Should I just try a 10 A fuse where I switched it to 7.5 A or will that lead to my new 7.5 fuse going out?

 

[peterg]

Could you post your wiring diagram?

 

[gggGary]

See GLJ post below; yes go back to 10 amp in the fuse block.
Get a digital voltmeter on the bike that you can see while riding, do not go up on the fuse size, My suspicion is that you have no voltage regulation and that volts just keep on climbing with RPM, the higher the voltage goes, the more the ignition coil draws, til it blows the fuse. Increase the fuse size and it is likely the pamco will get scorched again. Do not rev it beyond 15 volts on the voltmeter. Check your battery, high voltage will ruin a battery also.
No voltage regulation could be: wiring mistake, wrong type voltage regulator for your rotor/brushes set up, poor or missing ground connection, Also we have seen many "inexpensive import" voltage regulators fail to an always charging state.

 

[peanut]

, My suspicion is that you have no voltage regulation and that volts just keep on climbing with RPM, the higher the voltage goes, the more the ignition coil draws, til it blows the fuse. .

good call gary ...
I now wonder how many other pamcos have been fried by over voltage especially on batteryless bikes that use capacitors.
That said I'm sure pamco have over-voltage protection but I guess continual over voltage from the charging system would eventually blow the fuse or damage the pamco circuitry.

 

[member3480]

If you are running a stock harness I would check the grounds. You can also try this and keep the fuse in line with the 12 volts to PAMCO
First take a 16 gauge wire and run it from the battery ground right to the bolt that the coil is mounting too. This will make sure you are not having jumping grounds on you harness and frame.
Second right from the battery if not using battery get one and 12 volts to Pamco fuse
Go for a ride if fuse doesn't blow you have a floating ground and you will get spikes from your reg/rec
I have had more than 3 bikes with floating grounds that have had PAMCO or BOYER problems with blowing or heating up to a point and shut down.
The problem with all older bikes and just not xs650 is the design of the grounds and if running a stock harness its 35 plus year old and wires are poor.
Older bikes have many grounds and the are still all connected in harness but one or two that go bad can cause a problem.
I have had frames that could not show ground from rear of bike to neck because of rust.
You said you got 14 volts at 4000 rpm but that is with the bike standing still . Hook up a volt meter and go for a ride and see if it spikes
Older bikes need much love and deep pockets is some cases and buying something new does not mean its going to work 100% when you attach to old. Just doesn't work that way. Most restore people start with old and make everything new and sometimes you get lucky with old and new .
I burned up my very first PAMCO I ever bought because I did old with new and a bad handlebar switch did me in. Now 100 plus electronic ignitions later I test test test the harness before I fire up the bike or I just throw the old harness in the trash and make a new one if it look old and broken.

 

[GLJ]

I put a 7.5 amp fuse in line with the coil from the power and changed the 10 amp fuse in my fuse box to a 7.5 amp one to protect it.

it quit on me only for me to find the 7.5 amp fuse in the fuse box had blown. (not the one I installed directly before the coil)

If I'm reading this correctly you have 2 7.5 amp fuses in series. I think you need to go back to the original fuse for the fuse block. The fuse added for the coil/PAMCO is there just to protect the PAMCO. The fuse in the fuse block carries the load for more than just the ignition.

 

[JE4570]

If I'm reading this correctly you have 2 7.5 amp fuses in series. I think you need to go back to the original fuse for the fuse block. The fuse added for the coil/PAMCO is there just to protect the PAMCO. The fuse in the fuse block carries the load for more than just the ignition.

Yea so basically I have the fuse box with the 4 automotive fuses. There was one that was originally 10 amps that i switched to 7.5 A as recommended by some for the pamco. Then I added a blade fuse right off the power connector for the coil which has a 7.5 A fuse. I will try switching the fuse box back to 10 A like it was before the pamco should still be protected by the 7.5 amp blade fuse i added by the coil. The worst that could happen is the blade fuse will blow this time and I’ll have to pull the tank off on the side of the road.

I will also hook up a volt meter some how that I can view while riding to rule out charging. I can probably ghetto rig something with the volt meter I got and some alligator clips.

 

[GLJ]

If possible connect voltmeter + to the power wire going to the coil and and the voltmeter - to the same place the PAMCO is grounded.

 

[gggGary]

LED voltmeters are dime a dozen these days. a handlebar mount usb charging port voltmeter with on off switch quite handy.
https://www.ebay.com/itm/3-1A-Water...756619?hash=item3d87d2fd4b:g:m98AAOSwmYhcqJEi
I tend to wire them with a 3' cord to a SAE plug matching charging pigtail so can easily be plugged un plugged moved bike to bike.

 

[JE4570]

I swapped the 7.5 fuse back to a 10 A fuse and was able to ride around for an hour with no problems. I’m waiting on a voltage display to arrive in the mail so I can monitor my charging.