lights flickered and then bike died

[NewHavenMike]

Hello guys. Well I couldnt resist and decided to take my bike out. felt really good lol. First ride went well no problems at all.

Second ride was a different story. I didnt plan on going for a ride, rather just going to the store down the street.. Well, I changed my mind and went for a ride anyway, keep in mind that I left my phone at home and only had $20 on me and my little double headed screwdriver that I use to adjust the fuel mix.. Well Im riding and things are going well, I decide to head toward home and Im at a light. I look down at the neutral light and I notice its pulsing with the engine idle. Bike runs fine and I continue about 1 1/2 miles.

Then Im at another light waiting to take a left and the bike just died on me. I push it over and I have no power at all. My first thought was dead battery. Then I check whatever components I can and wires and fuses. I mess with the fuses a bit and some other stuff and then I had power again.

I push the start button and it turns over just fine. Im not getting any spark. I tested the rectifier and its OK.

I still use the mechanical regulator and I have a Pamco ignition. I ordered a modern fuse box in the meantime.

I really hope its just the mechanical regulator the busted? any ideas before I replace everything?

 

[BBS360]

Go with the new fuse box first. Even with the tiniest bit of corrosion those old glass fuses can completely stop conducting.

 

[NewHavenMike]

Yea I kinda came to my own conclusion after I posted this. I know its very simple. I wanted to make sure it wasnt something electrical and internal to the engine.

I found a website that sells a rec/reg combo for the XS360. Its a plug and play part. the website is: http://www.regulatorrectifier.com/catalog/1976-1977-yamaha-xs-360-xs360-regulator-rectifier

Anyone know of this place?

I have a fuse box on order now but I may change my mind and get some inline fuses instead and eliminate some of the wire harness.

Rewiring some of the bike has been on the to-do list anyways since its a mess. Theres a bunch of unused connections and length or wire that is not needed.

 

[NewHavenMike]

OK so an update here. I made up a new fuse box and bought the combo rec/reg setup that was plug and play.

Hook my battery up to juice and turn the key. Electrical powers up and looks like its ready to go. I check for spark and Im getting nothing. Naturally, my next conclusion is that the coils burned out. Thats an easy fix so Ill prob just get new ones anyways and have spares in case its not them.

Next, I had a look at the Pamco unit on the side of the cylinder head. It looks like a resistor burned out on both circuit boards. I guess this could be from leaving the key and switch turned on too long but I cant seem to recall when I ever did that. Anyways, this happened on my bike when I was riding it in the middle of the day.

I did remove the condenser as the instructions said I wouldnt need it anymore and also kept the 10 amp fuse. Should I have stepped down to a 7.5 as I have no condenser? How can I contact Pamco Pete about a repair/replacement? Ive emailed hime before but it mustve been a dead email address.

 

[spectra]

I emailed him off his website and he answered.

He is also on the XS650 forum so maybe try there ?

 

[NewHavenMike]

It seems he has a seperate email for every bike he makes parts for? Not sure if they all link to one account or what? He also has a website for every bike he makes parts for, sort of confusing. I emailed him through a CB email address and linked him this thread.

 

[pamcopete]

You may have had an overvoltage condition that fried those capacitors. Try just cutting them out.

 

[NewHavenMike]

Thanks for a response. OK i will remove them from the board. At this point should I be looking for a spark? Are they not a necessary part of the assembly? Is it only need when you still have a mechanical advance?

 

[NewHavenMike]

Pete, I have removed the capacitors from the boards. Im not getting anything.

Ive replaced the mechanical regulator and rectifier with a new combo unit.

Ive tested the both coils and they are good, even bought new coils just to be ready in case they were bad.

I bought and made a new fuse box and charged the battery up.

What next?

 

[NewHavenMike]

Well, I had some time today and I removed the Pamco and reinstalled the old points. It fired right up, runs rough but it starts. so its definitely the Pamco. I wonder what couldve happened if the coils didnt burn out when the Pamco burned?

 

[BBS360]

A short duration voltage spike could certainly blow the capacitors before the coils. Once the caps blew the coils may have been disconnected, protected by the blown caps.

A couple little capacitors shouldn't cost too much.
If the part #s are legible you should be able to look them up on digikey or Mouser and have new ones in a couple of days. Maybe even a local electronics shop.

 

[NewHavenMike]

I think I found the capacitor, but its rated at 50v.. I was kind of thinking that it would be much more than 16v but i really dont know. Theres also a bunch that are exactly the same with extra numbers.

 

[NewHavenMike]

I know youre probably busy Pamco Pete with your other products so I understand the delay in response. But I do not know what to do at this point with my ignition unit.. I do not want to make things worse by fiddling around with the pickup boards and wires. Im the kind of person that when my attempts fail, I may end up destroying the whole thing lol and making it non recoverable lol.

Please let me know when you can, what I can do to get this resolved. It is warm enough to ride at this point and im getting antsy.

I also picked up a 79 XS400 recently and im excited to have another go around on this platform.

 

[NewHavenMike]

UPDATE: So after all of this happened with the Pamco, I switched back to the points ignition and bought a new reg/rec from a sort of questionable website known as http://www.regulatorrectifier.com/catalog/. Well I drove around for a while, a good 45 minutes and everything was OK. Then It started getting dark out and I turned the lights on and the bike acted funny until it just stalled out. Id wait a couple minutes and some power would be restored enough to start it but the lights were VERY dim and then it would just die again. The battery never went completely dead but turning lights on would kill it..

So I bought a new battery since the one I had was beat on, Took it out in the dark and the same thing happened only after about 15 minutes.

Ok, now something isnt right. I tested the alternator/coils on the engine using the volt meter and the manual.. Everything is fine. Start it up and monitor voltage output to the battery and give it a couple revs. No increase whatsoever, stays at 12.3v (after starting the bike and had some V drain). So, I disconnected the regulator harness of the new rec/reg and hooked the old mechanical one back up. Started it and now im somewhere near 13.6v at idle. Revved it up and getting 14.5v. The mechanical reg came into specs after I tweaked the adjustment and seems to be working fine..


After all of this, I still cant explain why the capacitors on the Pamco blew. Is it possible that something could have stuck in the regulator to cause the volts not to cut off and it shot over 16v?

 

[BBS360]

It does sound like there must have been some kind of spike.
I wanted to say maybe a shorted rectifier but you said you tested the old one.

I've been considering trying a Pamco on my xs360. It fortunately already has a modern MOSFET reg/rec to put a hard limit on voltage output, in addition to a standalone regulator.

 

[NewHavenMike]

So you have 2 regs? Or you only use the rectifier part of the combo unit?

Whats this mosfet part you bring up?

 

[BBS360]

I have two different style of regs. I've put a modern reg/rec from a CBR125 in place of the stock rectifier but still have a regulator in the stock location too.
The stock regulator controls the field coil to regulate the voltage up to 14.5V and the CBR regulator rectifies and regulates the output down to 14.5v.

Doesn't help with low rpm charging but reduces voltage spikes, keeps the voltage stable for AGM/lithium batteries, and might help with modern electronics.

That's the theory anyways.
Everything tests great up on the center stand but haven't run the setup too long.

Now that I think about it I might bolt the stock rectifier back on somewhere so I can easily swap between connectors and try one for a few km, then try the new one for a few.
Need to diagnose something that could be a power drain.

 

[NewHavenMike]

OK I think I found a potential problem. My regulator is now putting out 14.3-14.5v at idle and when i hit the throttle it goes to about 15.5v.. I guess I need a new regulator.. I tried tweaking it more but its just not responding at all. I wasnt getting readings this high yesterday when I first put the reg back on.

The reg/rec combo I bought was $100 and doesnt work.. I do not know what one to get? I tried using the later style reg because its very small but that ended up not working either..

Im nervous to ride my bike now after being trouble free all last Summer/Fall.

 

[BBS360]

Not sure why the one you bought wouldn't work since it says it's specifically for the 360, unless the listing is incorrect.

If you tried to put a later xs400 electronic regulator on a 360 it wouldn't work without some modification to the wiring to the alternator.
The mechanical regulators supply a controlled positive voltage to the field coil, which is grounded.
On models with electronic regulators the field coil is supplied full +12V from the ignition switch and the regulator controls the path to ground.

Both use the same green wire so if you put an electronic regulator on an XS360 it's like attaching both wires from the field coil to ground.
Nothing happens.

To use a later model electronic regulator on a 360 you would have to disconnect the field coil ground wire and attach it to the wire from the ignition switch.
It's possible the combo unit you bought is meant for later model XS400s and someone just assumed it would work for XS360s and listed it as such.

 

[NewHavenMike]

The plug for the regulator side of the unit has only 2 wires, green and brown and they both match up to the harness on the bike. The mechanical reg has 3 wires, I assumed that the new unit paired up the ground wires so the ground on the rec harness is good for both sides of the unit? Ive been trying to cross match the wire diagrams between the 360 and the 400s and im 99% sure the wires are in the right spot.

This is the most confusing part of the bike for me.