Magneto Winding Circuit Req'd

Have sheared all the bolts off the starter clutch, and damaged the magneto windings.

Happy to rewind but it has been impossible to trace windings as i removed them, because of the extent of the damage.

Could just do with some guidance, even as basic principles.

Assume one circuit is for ignition and the other for lighting only when engine is running

Any help appreciated, as replacement cost is £300 dealer says

This recently happened to me. I wasn't skilled enough to rewind the stator so I bought a new one through Rocky Mountain. A bolt head also embedded itself on the inside of the flywheel so I had to buy another one of those also.

Have sheared all the bolts off the starter clutch, and damaged the magneto windings.

Happy to rewind but it has been impossible to trace windings as i removed them, because of the extent of the damage.

Could just do with some guidance, even as basic principles.

Assume one circuit is for ignition and the other for lighting only when engine is running

Any help appreciated, as replacement cost is £300 dealer says

Not sure how many poles, ie 2 or 4, and is 2 used for lighting, while other 2 for charging system? I suspect this is the case. You need to count the wraps and measure the wire size, it needs to be exact or output will be too much or too little. Too much might sound good to some, but the extra heat, its unable to cool, could burn itself out. If its a 4 pole, one system, one pole will need to be wrapped CW, next CCW, then CW and finally, CCW. I suspect its 2 seprate systems, ie lighting and a charging system. In that case, opposite poles will be for each system, so the opposites need to be wound opposite direction. End result, you will have 4 wires, one pair for the AC lighting, the other pair will need to go through the rectifier/regulator and charge the battery. I assume you have magnet wire on hand? And have the means to dip these in varnish and bake them? Make sure the pole pieices are well insulated first. Otherwise, the vibration, the wire will eventually chaffe to ground. Make sure you wind the wire up nice and uniform, avoid crossing across other wires, wind it up like a winch spool, ie left to right, then back. I suspect a wiring diagram would give you a good idea as to the setup, ie 1 system with 4 poles, or 2 seperate systems, each with 2 poles. Dont know if this helps. I have expereince in DC and AC motors, charging systems, etc. and I have rewound rotors, armatures etc.

Hi

thanks for your comments

The stator has 12 poles, i tried to trace wire routing when removing wire ,but with so much damage it was impossible.

Appreciate there are 2 circuits as there are 4 wire ends.

I'm confident enough to rewind its just finding out which poles and how many

Wire size is 1mm and i can purchase that laquered

Could you help any further ?

Thankyou, John

Hi

thanks for your comments

The stator has 12 poles, i tried to trace wire routing when removing wire ,but with so much damage it was impossible.

Appreciate there are 2 circuits as there are 4 wire ends.

I'm confident enough to rewind its just finding out which poles and how many

Wire size is 1mm and i can purchase that laquered

Could you help any further ?

Thankyou, John

John, I PM'd ya back. But for the others, here is my reply:

John, if there is 12 poles, then 6 will be for each system. So each system will use everyother one. Did both sets of winding use the same sized wire? And did you count the wraps? And did both system use the same amount of wraps? This will be critical for your AC lighting, as too many wraps can increase volts. So you will need to pick out every other pole for the first system, (mark it with a felt marker or system "A") wrap one CW, then the next one CCW, then CW, then CCW... and so on. Now keep in mind, when I say "next one", I mean skip a pole then wrap the next one. You will end up with half of the poles wrapped, every other one will be wound the opposite direction (north and a south pole), and opposing poles will be opposite also. Opposite poles on the stator must be opposite polarity. Now with half of it done, do the next set the same way. Each end of each series will be your AC output (2 wires for each group of winding, 2 groups of winding for a toital of 4 wires).

Leave you enough wire on each end to terminate to a flex wire for the harness and careful withg the wraps, make sure the magnet wire clears cases, rotors etc. Then when its all done, the entire thing needs to be dipped into a laquer and baked. This makes everything stay put. You will need to sand of the ends of the poles after the laguer process is done.

The most important thing is wire size and wraps.

Hi John

If you will go for a new one think about the YFZ unit from TrailTech, it has greater charging capability but you need to go full DC convert.

It costs less than a OEM unit.

If you do rewind, make sure to take pictures and post them.

Have rewound my stator, and refitted to bike, new 12.9 grade bolts replaces the sheared starter clutch mounting all loctited in place.Left it overnight filled it with oil today, starter kicks in ok but will not fire up.

Shall check if i'm getting a spark at plug, but i'm very concerned i still have a major problem.

PS checked the 2 fuses under the seat, were ok, wondered if the circuit fuse was damaged when the wires on the stator were damaged ?

Not meaning disrespect, writing in full sentences encouraged, punctuation to be considered, much easier to read, hard to translate and/or read, my point getting across?...SC

Your going to have problems unless you match the exact setup as stock. On the WR2540/450, the CDI looks at the stator to see if it should let the bike start.

If you wind to a single output, you can run to a single phase regulator/rectifier and get the bike going: Use 16 AWG wire for the rewind. It will look like this:

Stator-WRF250_450_w450.jpg

The wiring is shown below (it is pulled out for clarity). The power cable (one red going to two reds) is feeding 12VDC to the lights and battery (upper left). The two yellows are the single phase output from the stator going to the full wave reg/rec. The Red/White is the ignition trigger to the CDI. With this type of setup, you are full DC (lights dont go off when the motor stalls).

WR450_Conversion.jpg

Geoff

Okay, intended to rewind as standard so this will maintain current AC for lights

Only four wires come out of crankcase red & white are the trigger wires, confirmed and resistance is OK

Other pair are yellow & white so these must go to reg/rec unit,so i disconnmected these connecteed up multimeter to read AC volts, hit the elec start, motor spins over and detect a miserable 0.01v.

So my rewind has not worked, any ideas ?

Could i of wrongly assumed that the 2 groups of 2 connectors on the stator are not the paired ends of the 2 seperate winding circuits ?

Can i check by any other way ?

Have removed the newly rewound stator, as when tried i have no spark at the plug.

Think the terminations are incorrect, if you could please advise ?

Stator has 2 pairs of connector blocks lets say A and B

A1 is connected to the White wire which is the Charging coil circuit

A2 is seperate to A1 (electrically) and is connected to the body, so thats the earth

B1 is connected to the Yellow wire which is the Lighting coil circuit

B2 is connected to B1 (dual connection block)

How its wired currently, not working !

Coil circuit Z is connected to A1 round the poles and back to A2

Coil circuit Y is connected to B1 round the poles and back to B2

Logical i thought, as original wiring was untraceable

however there was only one wire connected to each connector block

Think i'm very close to the solution Please HELP

John

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