Archive for the ‘Elec – PM Alternator’ Category

XS650: Ants’ PMA   Leave a comment

Sourced and installed the parts from an RD350LC PMA into my blue rat some years ago . Used. Old. And still good. Very happy with it.

A year or so ago I picked up a nice low mileage 77 D. Ridden a few miles every year. Complete paper record. Had some charging issues.

About this time Ants from the British XS650 forum began providing new PMA units for a good price. 200W. Complete with rec/reg, a rotor cone key that fit the original XS650 crankshaft and timing marks. (if trying the link dont be put off if you get a blank page – simply reset and it will appear – dont know why it does this but it happens to me all the time)

Ants’ PMA kit

Was pretty busy for a while and it sat. Eventually got a chance to blow the dust off and begin.

Checking that the stator screws were loctited in – Yes.

Sometimes this locating pin just wont come out. Easier to quickly modify the backing plate.

The pin sits at 6 o’clock so a simple line perpendicular to the horizontal gives the position.

Backing plate didn’t sit properly over the crankshaft seal boss so got busy with a file. Would have been quicker to head off to the workshop and chuck it in the lathe. Naya.

Took a little while.

Sits perfect now.

Cut-out and reshaping will be now be done during production.

Phase wires held in place with a clip. Used another on the plate screw to the right just to keep clear from the chain and secured cable with a frame tie just below the rear engine mount.

Also removed the blue neutral indicator wire from the old loom, resheathed it in 4mm isolating sheath and reconnected to the original position. (Plug connector upper left in next pic)

This is the original regulator. Remove it. The rectifier too. Sits under the battery box.

Remove the battery to release the rectifier.

Made a plate to mount the new 5 wire rec/reg in the original reg position so the fins didn’t block the airbox inlet. Would have welded tabs directly to the battery box but had run out of wire for the MIG. The 3 screws with nuts create an air space under the rec/reg for cooling and better air flow to the filter-box. Packed with rubber bushes they dont rub against the underside of the rec/reg.

Fits snug between the tool box and filter-box. Cables separated, resheathed and fitted with original connectors.

Release the original connector blocks by inserting a small flat bladed screwdriver into the recess beside the pins. Simply push out.

Make sure the tangs are reset before reusing.

All connected. Added a 20 Amp flat bladed fuse holder in the positive battery feed. Just for security. This wire is too long and will be reworked.

The rec/reg, when mounted on the plate, interferes with the sidecover. Modified an old sidecover. Rattlecan-blacked it and it’s mate. Be a shame to mess up a good set of covers

Just got to put some kms on her now to road test before installing a 750 kit that’s been sitting on the shelf for a couple of years.

Had some charging issues in the beginning. Went through and checked the new wiring. Not quite sure what was wrong but the issues disappeared.

More than happy with this.

Update … almost killed my second rear tyre now – no problems – running sweet


XS650: Boyer Power Box   Leave a comment

Boyer Power Box


The power box is a self regulating rectifier with an internal current and voltage storing capacitor. Connecting directly to the alternator, the output is approximately 15 volts with no current being drawn and 14.5 volts with some load. These values are just right for charging a 12 volt battery or running the electrics direct.

The unit has been designed using the latest power technology semi-conductors to provide stable, direct current from standard permanent magnet alternators.

Three types are available: Single phase, Bi phase and Three phase.

Some are available with a charging lamp control, or lighting delay circuit, which prevents the lights being turned on until after the engine is started. Ensure you have the desired unit before fitting. Single phase and Bi phase units control 200 watts and three phase units control 300 watts.

As a rule of thumb Single phase power boxes are suitable for use with most British Bikes, pre 1975 with alternators two, or three wire. Bi phase are suitable for use with most Italian and French machines equipped with three wire alternators. Three phase will suit some British machines post 1975 with three wire alternators and the majority of Japanese three wire machines.

For further info go to the Boyer site.

XS650: Simplified Electrics   Leave a comment

There are distinct advantages to doing this. Original looms had circuits, relays, safety devices, checkers and stuff that did their job back then.

Time, vibration, water, oxygen and irregular maintenance have all compounded producing electrical systems, already lacking good fusing, that will provide you with endless hours of frustration.

I rip them all out. Can’t be bothered with the drama. Make them new. Myself. With central blade fuse box. 1 for each circuit. I get a new system. Custom designed for whatever I need. Easily modified. New cables. New connections. Soldered. Crimped. Isolated. And I know what I have. Diagnosis become heaps easier.

First time you’ll freak. Second time you’ll wonder why.

Here is one of the best. An all rounder. If you can look at this and understand it you will know more about original electrical systems than most. It is elegant in its simplicity. Plug and play. Except for some peripherals it’s all there. Thanxs Jayel.

Jayel put this together, earns a beer from me…everything really except indicators…for original charging systems and ignition

Simple to adapt for pretty much anything.

doesn’t get much simpler than this…no battery, runs capacitor, permanent magnet alternator, twin coil, pamco, no real need for the key though-could put a second kill switch somewhere

The only thing simpler is total loss.

Good earth connections. Check your brushes. Maintain your battery. Fuses.

Note that if installing coated bars you may have problems starting. Check your kill switch earth connection. No earth. No go.


XS650: Permanent Magnet Alternator   Leave a comment

I don’t want to knock the original generating system. It has functioned for the last 40 odd years in one form or another. Designed to be in balance with the machine itself. And it has functioned. Mostly well.

These are Hitachi-no GM here-and have mostly given dependable service. But then 40 years ago I was a teenager. Pumping. Today I’m learning my physical limitations.

It has it’s shortfalls. Don’t you?

If you’ve ever been stranded, using an excited charging system, with a weakened battery or worn brushes you’re going to start thinking the sun has to be shining. Somewhere else. Don’t get me wrong. They are not Lucas. Thankfully. But you’re still stranded.

This topic has been thrashed by now. Over at the Garage, here and here or the Oz site or here.

I remember this discussion starting up some years ago. There is a long thread at the Garage if you want to sort through it. It’s kind of interesting seeing it all develop. Here in Germany this mod has been done for a very long time now. Getting hold of the parts required is not as cheap as it used to be.

This is basically a plug and ride mod. Will take a tech. novice with the parts and basic tools a morning to complete a points bike. A little longer for an electronic ign model.


TCI pickup in the black box 13.00…brushes are isolated…earthed through the rec.reg… if converting to PMA you will lose this and your original electronic ignition


points models have this advance unit on the right hand end of the cam, points to the left


If your bike has a crank-based electronic ignition (TCI) you will need to swap this to a cam-based ignition (points, pamco…). This does introduce some timing errors associated with valve timing. Stretched cam chain, improperly dampening chain adjuster, cam lobe wear, valve wear, malfunctioning ATU etc will all directly affect cam-based ignition timing. But. Don’t worry. The points ignitions on all other XS650s are cam-based and they run just fine.

the complete ATU mechanism..passes through the cam


If swapping from crank (TCI) to cam-based ign you will need to source the ATU-as above-if using points or Pamco. This is the shaft that runs through the hollow cam and the sprung weight mechanism on the rhs. The points or Pamco fit on the lh end. Make sure there are bearings or bushes. A good time to upgrade your coils too.

There are several ways to do this.

  • Source an RD-RZ 250-350 LC/YPVS rotor and stator. ’83 on. (earlier LC-non YPVS have a lower output)


RD350LC/YPVS stator, rotor-not here, backing plate


backing plate dimensions



remove the pickup


you only want these 3 white wires = 3 phase, the rest are not required


  • Pick up a Rectifier-Regulator. An original RD will directly plug and play. New is preferable.


Ascension Cycle Works … pma adapter … ebay


  • Source a Mrriggs adaptor..ebay? Not so sure he is making them any more!! or Ascension Cycle Works … ebay
  • Get a stator only…103 x 42 x 20…mounts directly to the adaptor…endless lists in the links at the beginning
  • Find an RR from pretty much any late model high revving sports bike running a PMA. Some will have 5 wires, some 6, some 7.
  • The colour coding will differ with brand too. If  running without a battery, connect the voltage sensing wire, typically Black on Honda, Orange on Suzuki, and Brown on Yamaha and Kawasaki to the positive output wire. If running a battery connect after the ignition switch so it’s live only when the key is on.
  • Take care if ordering kits … some are only 2 phase … those with 3 white or yellow wires are 3 phase

Just found this which deals with the topic fine.

electrolytic capacitor…use the one with screw posts…25V 10000uF


You can run this batteryless using a capacitor…25V and 10K uF. I’ve done this for quite some time now with no problem, however I get a little nervous sometimes wrt reliability. I am about to add in a small gel battery. If my alternator stops charging my Pamco requires so little current I will still get home.

small gel battery


fitted, wiring laid


easily wired in…with or without battery


83-85 RD-RZ basic data … later 86/87 have VCD-88/ND AC Generators with 13A output@5000rpm


As I say, apart from a slight risk running batteryless I like this. After adding a battery I will feel good.

It’s a bit lighter, allowing slightly freer revving. For track purposes however a total loss system makes things even easier.

One more point here. These girls are starting to show their age a little, mostly gracefully. Personally I distrust the complete electrical system and usually take this chance to rip the lot out. I then fabricate my own simplified wiring. Doesn’t take long, reduces weight, makes space and you know what you’ve got.