Bike wont start

[pat_in_the_hat]

Pamco Fried, again

Last week I thought I had this project done. Was running amazing and I prob put about 20 town miles on it. It was perfect.

But then when it was running down a main street it just stopped. No sputter, just died. Felt like someone just flipped the kill switch. Wouldnt start back up. I thought it was the battery so I got a brand new one. Still wont start. Checked all the wiring and it all looks good. Fuses still intact.
However, I noticed when I have the ignition on, the headlight wont light up. taillight and brake light does though. But it illuminates when I switch it to high beam. Low beam burnt out? It has a 10amp fuse...
ALSO,
When as soon as I flip the ignition switch, it backfires, meaning it has spark, correct? But, when I kick it, I dont get a spark.

I know you guys know these bikes inside and out. So I really hope someone might be able to help before I give up.
Any ideas/suggestion/ANYTHING? please?

 

[pat_in_the_hat]

well. looking through the pamco I found this

my pamco is fried. bummer.... now to figure out what went wrong, how I need to fix it, and what I need to order to fix it

 

[Conrad Russell]

I dont know why the pick up failed but you can get a new one threw Pamco-pete.

 

[pat_in_the_hat]

Alright, I may have to do that. First though, I would like to figure out why this happened so I wont be stuck with this headache again. And if my coil is still good. I just saw that this can happen from a bad resistor?

 

[JP50515]

Mine did the same thing....twice....even after installing in line fuses to prevent it....what are you running for a reg and rect? I believe the reg is where my issue lies.

 

[pat_in_the_hat]

Mine did the same thing....twice....even after installing in line fuses to prevent it....what are you running for a reg and rect? I believe the reg is where my issue lies.

yea. I have a 10amp fuse before the ignition. Im going to go down to a 7.5amp on this next try. Im running stock alternator and rectifier. Im wondering if I switched to a combination rect/reg, or at least something newer that has a better chance of working if this wouldnt happen again.

 

[pat_in_the_hat]

alright. so I did some checking with a voltage meter.

Coil primary restance of 4.5 ohms GOOD
Coil secondary resistance of 16k ohms GOOD
rotor has a resistance of 5.5 ohm between rings. GOOD
rotor ring to ground on both rings is infinite. GOOD
stator resistance between white wires is all .7 ohms. GOOD

The only thing left I could think of is the regulator and rectifier. But I cant test without the bike running. If I replaced the resistor with a new combined reg/rect for points ignition bikes, would I have a better chance of not frying the next pamco?

Main question is, would a bad regulator or rectifier lead to a fried ignition system?

 

[pat_in_the_hat]

any other suggestions as to what could make a Pamco fry?
I would like to get this project done before it stats snowing here in Montana, which is always sooner then expected. Ive tried contacting Pamcopete but he must be a very busy guy with all these units out for these different bikes.

 

[retiredgentleman]

Ignition damage and a headlight (low beam) burnt out. I suspect you have had some extra high voltage. I can't know for sure if that is your problem, but I recommend you replace the old stock rectifier and regulator.

The stock regulator while it worked OK for many years, is mechanical and its worn out. The stock rectifier is an old design and its worn out as well.

These bikes run really well if you have the correct voltage (and a good battery). That means 12.5 to 13 volts at idle and 14.1 volts at anything over 1800 to 2000 rpm. The way to get that is to toss out the old rectifier and regulator and buy new replacements.

Don't waste money on a combined rec/reg. For your 1975, buy a solid state automotive nos VR-115 regulator (E-bay). Also buy one 3 phase rectifier (E-bay) or buy two bridge rectifiers from Radio Shack. The 3 phase unit will likely have a heat sink, but the dual bridge rectifiers need to be mounted on a simple heat sink. Total cost about 1/3 of the combined units.

 

[pat_in_the_hat]

alright, thanks for the advice retiredgentleman. I went ahead and ordered the VR-115 and a 3 phase rect thanks to ebay. It was a bit cheaper then the one combined unit. Hopefully that fixes it.

Now just waiting to hear back from Pamcopete. Whats the best way to get ahold of him? Ive sent him an email and personal messages, but after almost two weeks now, no response.

 

[pat_in_the_hat]

so still no word from Pete. Right now I am considering two options.

1. Figuring out what that part was that fried. It looks like a diode? But not sure its V or Amp. Anyone know? Then going to radio shack, or just ebay, and solder it in and hope it works.
2. Reinstall points the PO gave me when I bought the bike.

 

[5twins]

Well, for testing purposes to find out if the reg or rec are acting up, putting the points back in may not be a bad idea. You can't hurt them really, not like possibly frying the next Pamco.

 

[pat_in_the_hat]

yea thats true. but I realized that I dont have the original coils or the condensors. Plus i just got a new VF115 reg and a new 3 phase rectifier. So I should be good now in terms of reg/rect acting up.

I guess I just need to wait for Pamcopete to get back to me to order a new pamco, or try to replace that diode (?) that got fried on my first pamco

 

[xjwmx]

to replace that diode (?) that got fried on my first pamco

You might as well try unless it voids a warranty or something. According to this pic it is a diode. For this application any commonly available diode of the approximate physical size would work, might be called a power diode at rs, and it'll do. Mount it with the band on the end in the pic. Don't get a zener.

http://www.amckayltd.com/PCBoard1.jpg

I would like to get this project done before it stats snowing here in Montana

Could be any day, and not thaw until same day next year

 

[pat_in_the_hat]

You might as well try unless it voids a warranty or something. According to this pic it is a diode. For this application any commonly available diode of the approximate physical size would work, might be called a power diode at rs, and it'll do. Mount it with the band on the end in the pic. Don't get a zener.

http://www.amckayltd.com/PCBoard1.jpg



Could be any day, and not thaw until same day next year

AWESOME! Thank you very much! This is the answer I need. Im sure the warranty is up on it as the PO bought it with this project a couple years ago, but never finished the bike or put it on. Heck, the Pamco only ran for about 20 miles. But I think ill go to radio shack and see what they have. Any diode will work huh?
And you know it about the weather. One week its pushing 90's, the next its snowing and wont stop until who knows when.

 

[xjwmx]

I spent last winter in eastern MT. It was in the 90s in Sept but once it started snowing it didn't stop til about May. I was trapped for a month after I wanted to leave. But it's a nice place for a certain lifestyle. Sharp rural people, which seemed kind of different.

 

[pat_in_the_hat]

Yea I have lived my whole life in Montana. I absolutely love it and I hope I never leave. The winters can be very rough, but it just makes you appreciate the summer even more. Plus with the skiing we have here, sometimes the winters can be even better then the summers.

Anyway, I went to radio shack with the Pamco. I showed it to the guy and asked if I would be able to just replace the diode. He said no. I guess the board got hot enough that it burned some of the wires inside the board. Im no electrical engineer, and know very little about electrical things, so I take his word for it. He said I would be able to take it to a computer repair shop and they will be able to make me a new one. But, I have a very strong feeling that would cost more then just replacing it through Pete.
So now I guess I wait until Pete responds to me. Hopefully Im not too far down on his waiting list haha

 

[xjwmx]

I figured you were going to do it yourself. A repair place might do it for free because it would only take a couple of minutes. Another possibility is a music store that has a repairman. They do more soldering than anybody, switching guitar pickups and repairing amps. I don't know if the diode will fix it and I don't know for sure I suggest the right diode but it's a good educated guess. I couldn't find a schematic for the Pamco anywhere. I'd put the diode on for free if I had a shop and somebody brought everything in.

 

[pat_in_the_hat]

well I was going to do it myself. Just a quick solder job. But the guy was saying that the board itself got hot enough and even if I just soldered a new diode on, it still wont work. He was saying that it would be a waste of time and the only way to fix it is to get a new one made.

 

[xjwmx]

Nah, not so. Even if the trace was wholly burned off the board you could just run a thin jumper where it used to be. It's just a simple board, no traces inside between layers. Surely.