PMA conversion.

toglhot

Active Member
The TX650 came stock with an electro magnet alternator, a popular mod is a PMA using second hand parts from various bikes and bodging up a Banshee mount to fit. Otherwise you can buy a new conversion kit from many of the XS specialists.

I baulked at the price of the kit, around $400/$500. I also didn't fancy using 40 odd years old parts and a bodged up mount.

I found new parts on ebay: a stator ($50) and reg/rec ($25) for an XV, and rotor for a Banshee ($60) for an all up cost of $135. Using a slab of ally I had lying around in the shop I spun up a mount to fit the stator to the TX. I didn't have a piece of ally the right thickness (45mm), so made the mount in two pieces.

The keyway on the TX crank and rotor is 5mm, whereas the keyway on the Banshee rotor is 6mm so I had to step a woodruff down to fit. I then found the diameter of the woodruff was too big, so the woodruff didn't fit all that well, so I turned up a piece of stock to the correct diameter, sliced it in half, stepped it and shaved it down until it fit.

Timing is normally done on the TX using the alternator rotor which has marks on it, the new Banshee rotor doesn't have these marks, so I refitted the original rotor, timed the engine, removed the original rotor, refitted the Banshee rotor, made and fitted a pointer plate and marked the pointer plate and rotor accordingly.

To make the lekrisity flow better I polished the mount. The experts should appreciate that one.

The reg/rec was mounted on an ally plate behind the battery carrier.
 

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Impressive! How did you get the information regarding flywheel weight and inner diameter so you could do the retrofit?
 
I didn't need flywheel weight, it's an alternator rotor so, it's weight would vary very little to the original.

Which inner diameter do you mean, inner diameter of the rotor where the magnets are, inner diameter of the rotor that fits over the crankshaft, inner diameter of the mount???

The only difficulty with the rotor is matching the taper of the crank to the taper of the rotor. There is a list of rotors with the same taper on the web and a list of stators that will work with the rotors.

For the mount, I took measurements of the crankcase and machined the mount to fit, missing all the little casting knobs and what not. To get the height right, I fitted the rotor over the stator, fitted it to the bike and took measurements again.
 
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I actually assembled most/all of the parts for a PMA conversion some time ago and never did it. I should dig it all out and see what I have, and maybe put it on the XS motor in my current decade-long project bike.
 
I didn't need flywheel weight, it's an alternator rotor so, it's weight would vary very little to the original.

Which inner diameter do you mean, inner diameter of the rotor where the magnets are, inner diameter of the rotor that fits over the crankshaft, inner diameter of the mount???

The only difficulty with the rotor is matching the taper of the crank to the taper of the rotor. There is a list of rotors with the same taper on the web and a list of stators that will work with the rotors.

For the mount, I took measurements of the crankcase and machined the mount to fit, missing all the little casting knobs and what not. To get the height right, I fitted the rotor over the stator, fitted it to the bike and took measurements again.
I should have been more specific but you covered it anyway :) I was referring to the inner diameter of rotor matching the taper. Do you still have that reference available you found? I'd like to add it my library for future projects. If not, I'm sure I can find it with some keyboard work.

Nice work!
 
On my XS, I used a VZ800 stator because of more charging capacity. Not sure if you're looking at the capacity of your cheap ebay stator, but I'd make sure it matches up or you're giving up the main reason for the mod. You also have to be careful of the cheap Ebay rotors, as they're known to fly apart.
 
I recommend a SH775 reg/rec unit. They are spendy new but can be found used for pretty cheap. Polaris used them on a bunch of things so I search ebay for polaris regulator, then look at the pics until I find one that's marked right. Keeps the stator and regulator significantly cooler since it shuts down phases instead of shunting excess to ground. I switched after the first stator I used burned up.
 
On my XS, I used a VZ800 stator because of more charging capacity. Not sure if you're looking at the capacity of your cheap ebay stator, but I'd make sure it matches up or you're giving up the main reason for the mod. You also have to be careful of the cheap Ebay rotors, as they're known to fly apart.
No,, I just chucked the first thing I came across on the bike, who cares about output.
 
No,, I just chucked the first thing I came across on the bike, who cares about output.
Was hoping paying twice the price for chinese parts would yield some benefit over the used parts. Still cheap enough to pay for new parts if they match up. It all looks good bright and shiney. Great job polishing.
 
Knock Chinese products all you like, but where do you think Mikes, XS direct and the rest get their parts from. You are simply paying top dollar for parts you can get much cheaper straight from China.
 
Knock Chinese products all you like, but where do you think Mikes, XS direct and the rest get their parts from. You are simply paying top dollar for parts you can get much cheaper straight from China.
This isn't about knocking Chinese parts. It's coming from building bikes for a long time and having bought hundreds of Chinese parts. I buy Chinese parts often, but it's not a comparable success rate to US or German made parts. I continue to buy them, but the comments I made about your parts comes from experience not prejudice. I have done this very mod multiple times, and I have been around drag racing since the 80s. I have seen the chinese Banshee rotors come apart at the rivets and magnets first hand. I have found a good Chinese made rotor that's reliable, so I'm not at all discounting using them altogether. I have personally seen all kinds of different issues, most of which results from a lack of quality control. I am not ciriticizing your decisions, but it's fair to promote caution, as I practice it myself. The style of charging system in the XS and Hondas like the CB650 are notorious for their charging issues, which this mod is supposed to fix. I don't think it's unfair to ask what the numbers are. If they're better, they're better. As I said, i do the mod with used VZ800 stators I can buy on Ebay or at swaps for as little as $10. I'd prefer to buy a new stator, and at $50 if it is comparable, it's worth the buy. I also have experience working with Chinese manufacturers. Yes, US companies outsource production to China, but the good companies maintain a strong quality control program for those parts. Random Ebay parts don't often have that.
 
Oh, I can beat that easy: I've been building customs since the mid 60s. I use Chinese parts almost exclusively, never had a problem. Using 40 year old parts is not a good idea, regardless of where they're made.

And like I said before, where do you think Mikes, 650 direct, et al, get their parts. It is pretty well impossible to avoid Chinese - anything in today's world. The machinery I use to create my parts also come from China.

Now if I compare my nice new Chinese alternator with an original Japanese XS650 alternator, it's chalk and cheese, the original alternator is as rough as guts, that's why they don't work well and why XS650 riders make the conversion, with most buying their conversion kits from the XS650 parts outlets.
 
Oh, I can beat that easy: I've been building customs since the mid 60s. I use Chinese parts almost exclusively, never had a problem. Using 40 year old parts is not a good idea, regardless of where they're made.

And like I said before, where do you think Mikes, 650 direct, et al, get their parts. It is pretty well impossible to avoid Chinese - anything in today's world. The machinery I use to create my parts also come from China.

Now if I compare my nice new Chinese alternator with an original Japanese XS650 alternator, it's chalk and cheese, the original alternator is as rough as guts, that's why they don't work well and why XS650 riders make the conversion, with most buying their conversion kits from the XS650 parts outlets.
I forget boomers come to the internet to have people pretend they're impressed, pat their backs, and agree with everything they say.

Wow, I can't believe you built a PMA kit for a fraction of what Hugh sells them for. And you make them so shiny. Great job.
 
Yeah, it's annoying. More annoying though is those that want to tell us they've been building bikes for such a long time, have loads of experience, therefore know it all and everyone should listen to them. When in reality they've been doing it for five minutes. These I call fwits!
 
Wow, it's a good thing we don't have any boomers, know it alls, or twits here. It sure would be annoying if we did.
 
Oh, I can beat that easy: I've been building customs since the mid 60s.
I hadn't realized that this was a competition based solely on how long you have been working on customizing bikes. SInce you have been building customs since the 60's, you have me beat by about 10 years so I would be foolish to make any comments about how you are doing any of these modifications. I sure wish I had credentials like yours, then maybe I could act like dick on here, too.
 
I hadn't realized that this was a competition based solely on how long you have been working on customizing bikes. SInce you have been building customs since the 60's, you have me beat by about 10 years so I would be foolish to make any comments about how you are doing any of these modifications. I sure wish I had credentials like yours, then maybe I could act like dick on here, too.
Seems to me you are acting like a dick. But you've totally missed the point dick. If you go back through the posts you'll see my reply was in response to your dickhead mate telling me he'd been around bikes since the 80s. Dicks like yourself and your dickhead made seem to like stating how long they've been working on bikes. I simply like to show up dicks like you and your dickhead mate for bringing up such nonsense. Otherwise I would never mention how long I've been around bikes, it really has no bearing, unfortunately, dicks like yourself and your mate seem to think it does for some reason.
BTW have I told you what a dick your are. Just in case I haven't - you are a dick.

Another BTW: Thanks for turning this thread into a full on free for all. Until you and your dickhead mate started, there weren't any problems. Do you behave like this everywhere, or just on this forum?
 
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