Why PMA

[Kinsygrl]

Ok, I need someone to convince me wether or not to invest in a PMA. Do they work on all years ( my boyfriend is building me an 81 ) is it an easy install and are there other modifications he would have to make. He is busting his can to get this bike done before the end of the riding season and we have about $500 in parts so far, so if his isn't an absolute must have we've thought about saving it for the winter to do list! It is quite an expensive upgrade ( if my memory serves me around $300 ) and we just don't know enough about it to justify one way or the other.

 

[jetmechmarty]

If you go the a PMA, you have to get a new ignition system as well. The '81 has the ignition pickup on the rotor. The weak point in the system is the rotor. If it is original, it will short out sooner than later. Once you have it rewound or replaced with a quality component, the problem is solved. After that, you just have to check the brushes once in a while.

I have a '83 with the same system. I've had it for 30 years and fifty one thousand miles. My rotor shorted ten years ago and it was replaced with a rewound unit. Somewhere along the line, my pick-up coil failed open. I replaced it with a used one for $10.

I've taken this bike on long trips. I'm happy with the stock system. As long as I can fix or replace the stock parts, it will stay that way. I just restored an '81 for my daughter. It is stock as well. It has the OEM charging rotor on it. I likely won't mess with it until it fails.

 

[smokedyerstang]

This is an old link from hugh explaining the pros of the pma swap. As mentioned, you will have to upgrade the ignition also but it is well worth it. And the install is not hard at all for any of it..

http://www.chopcult.com/forum/showthread.php?t=6604&highlight=XS650+Permanent+Magnet

 

[blackbetty]

It's probably the #1 mod you can make to increase reliability.

 

[gggGary]

Kinda rant on;

Sorry blackbetty but the #1 one mod for increased charging system reliability is a good battery, damn it. I have bought plenty of bikes with bad rotors I also have lots of 30 year old rotors that are still good. I haven't had a rotor fail on me yet but I ALWAYS have new or known good batteries in my bikes.
Bad battery, rotor works full time trying to charge it, rotor overheats, the insulation on the wire gets brittle and shorts out coil to coil. So check out your charging system parts, if they are in spec and you have good battery of reasonable size. Yes size matters, tiny little "hide away" batteries will torque the charging system and create failures. you are good to go
OK rant off,
Ride on.

 

[girouxmcisaak]

This is an old link from hugh explaining the pros of the pma swap. As mentioned, you will have to upgrade the ignition also but it is well worth it. And the install is not hard at all for any of it..

http://www.chopcult.com/forum/showthread.php?t=6604&highlight=XS650+Permanent+Magnet

Thank you so much for this link. The PMA upgrade just went from "something I begrudgingly will do with a kit since I don't have the stock parts" to "Oh, something I can do over time? Sweet!"

 

[xjwmx]

if his isn't an absolute must have we've thought about saving it for the winter to do list!

If your charging works there's definitely no reason to do it immediately. Don't know of any reason to do it at all, really. It's supposed to be theoretically more durable than stock, I think. But I think most people who do it just want to spend money on their bike. Sort of like giving a woman things she doesn't necessarily need...

 

[jetmechmarty]

Story Time

Back in 2002 I decided to ride my XS650 to my HS reunion. I had not had a trip on it in a long time. The trip origin was south of Atlanta and my destination was 50 miles east of Erie, PA. I decided to pretty much follow US 19 all the way. That would make the trip about 1,000 miles each way.

Back then, my social media came from the XS650 email list on Micapeak.com. I asked for advice about my trip. Someone suggested I carry a spare rotor and puller. I ignored that advice.

At about Murphy, NC, my bike quit. I replaced the brushes there on the side of the road and continued. On a long downhill stretch at Morganton, WV, my bike went dead. The main fuse was blown. I continued to Jamestown, NY without issue. I ran the bike around town visiting friends and relatives. After three days I pointed the bike south and returned pretty much the same way I had come up. Somewhere along the way, the main fuse blew again. Otherwise, I made it back home without issue.

I parked the bike in the garage where it sat for at least three weeks. One day, I hopped on it for a ride into town. I made it three miles! The battery was dead. I got the bike back home and discovered the rotor was shorted as in zero ohms between the rings. The gods had been watching over me!

Someone on the email list swapped me for a rewound rotor. The charging system has been fine ever since. About nine years ago I switched to an AGM battery. It's all good any more!

 

[retiredgentleman]

Great story there Marty!

Yeah xjwmx, there's nothing more dangerous than a women with a credit card, heading out the door towards the shopping malls.

Yes, the PMA has been marketed, on this site, as the greatest thing since sliced bread. The fact remains that many of us still use the stock alternator with great success. I suspect my rotor and stator are the original from the factory. 35 years is a long time, so will the alternator fail.................yes, probably some time. I'm prepared to wait until it fails.

Gary is right on about having a good strong battery................worth there weight in gold!

 

[Take Warning15]

I figure I won't swap anything until mine fails or I take a really really far trip. If it ain't broke, don't fix it, right?

 

[SPUd]

I think it all depends on what kind of mods you are doing to your bike. If you are chopping frame up and making cool bikes like most of us on here, a PMA makes a lot of sense due to the fact you can run really small batteries, or even run without one (using a capacitor).

This allows you the freedom of not needing some huge metal box that takes up valuable real estate in your newly fabbed up frame.

There is also the weight saving benefit of running with a small, (or no), battery.

If you are keeping the bike basically stock, and have the facility to run a decent sized battery in the stock location, and are not concerned with the weight savings, it's probably not one of the highest priority 'to-do's' that should be on your list.

 

[jetmechmarty]

I think it all depends on what kind of mods you are doing to your bike. If you are chopping frame up and making cool bikes like most of us on here, a PMA makes a lot of sense due to the fact you can run really small batteries, or even run without one (using a capacitor).

This allows you the freedom of not needing some huge metal box that takes up valuable real estate in your newly fabbed up frame.

There is also the weight saving benefit of running with a small, (or no), battery.

If you are keeping the bike basically stock, and have the facility to run a decent sized battery in the stock location, and are not concerned with the weight savings, it's probably not one of the highest priority 'to-do's' that should be on your list.

BINGO!

 

[XSLeo]

No matter how many people believe other wise the only real advantage to the PMA is that you can run without a battery.
all the other stuff is just rationalizing not reasons.
Leo

 

[79xs]

If your stock charging system works, then don't replace it, just replace your battery and carry some spare brushes. If your charging system is broke, its probably cheaper to replace the broken part, rather than replace the whole thing. If EVERYTHIG is shot, the PMA might* be the cheapest option.

When I bought by bike I replaced the regulator, rectifier, battery, tires, fluids, and rode it a lot. A year later the stator went bad. I got a replacement stator for $200, and my bike has been charging great for the past two years. For me, it made more sense to spend $200 on a new stator, since I knew that I recently replaced a bunch of other charging components, rather than drop $350-400 on a PMA.

Honestly, I do not understand why everyone on this forum is obsessed with PMA's and PAMCO ignitions (no offense to people who love them, they seem like quality products). Maybe I'm just old school, but its REALLY EASY to periodically check your brushes and points, and carry an extra set. Its also WAY cheaper to stick with the stock setups.

As previously said, if you want to run without a battery, then the PMA is a must. Otherwise, I don't see the point...

 

[shotgunjoe]

My first ever xs650, had a bad charging system. The rotor was bad, the brushes were bad, and the regulator was bad... at the time, the price to get new parts was around $600. The PMA swap wasnt available as a kit, it was still in its infancy, and most were against doing it at all... research revealed that it was possible to do the conversion using all stock yamaha parts, and with the deletion of the slip rings and brushes, that means less maintenance. I paid $75 for my PMA and another $25 for the correct reg/rec, all used OEM yamaha parts... my first ever experience repairing a motorcycle charging system, it was about the same or less than a rewound rotor, and worked perfectly out of the box.

My assessment? Less parts to fail = more reliability.

 

[SPUd]

My first ever xs650, had a bad charging system. The rotor was bad, the brushes were bad, and the regulator was bad... at the time, the price to get new parts was around $600. The PMA swap wasnt available as a kit, it was still in its infancy, and most were against doing it at all... research revealed that it was possible to do the conversion using all stock yamaha parts, and with the deletion of the slip rings and brushes, that means less maintenance. I paid $75 for my PMA and another $25 for the correct reg/rec, all used OEM yamaha parts... my first ever experience repairing a motorcycle charging system, it was about the same or less than a rewound rotor, and worked perfectly out of the box.

My assessment? Less parts to fail = more reliability.

This.

Like everyone has said, there are many sides to this argument, and the main point is basically if you want to run without a battery, or with a tiny one.