12 or 18 Pole Rotor.

[Guest]

I found out that my stator was bad, so i took it apart and found a 18 pole stator in it (its a GS750 from 78) so i replaced it with a 12 pole - that should fit that years model. Been having charging problems since i bought the bike.

- Still having issues my next guess is that the Rotor has been replaced with a newer one that takes a 18 pole stator.

Is there some kinds markings indicating if its a 12 or 18 pole rotor, or is there a way to meassure it?

Thanks!

[Steve]

With the cover (and stator) removed, use a piece of metal that you won't mind if it gets magnetized, and run it around the inside of the rotor. It will pull and stop in several locations. If it pulls in FOUR spots, you need a 12-pole rotor. If it pulls in SIX spots, you need an 18-pole rotor.

I have some of each being re-wound right now, so don't have any available.

.

[Facius]

With the cover (and stator) removed, use a piece of metal that you won't mind if it gets magnetized, and run it around the inside of the rotor. It will pull and stop in several locations. If it pulls in FOUR spots, you need a 12-pole rotor. If it pulls in SIX spots, you need an 18-pole rotor.

I have some of each being re-wound right now, so don't have any available.

.

Thanks Steve, i'll check it out!

[Facius]

Ok, so i checked the rotor today. but it doesn't really make sence with the 4/6 pull points Steve mentioned.
There are 4 visible sections in the rotor, each with 3 pull points which corresponds to 12 poles, so am i right in assuming its a 12 pole rotor/stator?

I have created a small illustration of what i mean:

[tom203]

The 18 pole stator has 6 pairs of north/south magnets- they run alternately around the rotor. Get a refrigerator magnet ( 3/4 inch diameter or so)- this magnet has a N face and S face . Pick a side and run in along inside rotor. It will be attracted 6 times and repulsed 6 times (alternately)as it meets the rotor's magnets.
The 12 pole stator only has 4 pairs of N/S magnets in its rotor.

[Facius]

The 18 pole stator has 6 pairs of north/south magnets- they run alternately around the rotor. Get a refrigerator magnet ( 3/4 inch diameter or so)- this magnet has a N face and S face . Pick a side and run in along inside rotor. It will be attracted 6 times and repulsed 6 times (alternately)as it meets the rotor's magnets.
The 12 pole stator only has 4 pairs of N/S magnets in its rotor.

Thanks. I did the magnet trick, and i got 6 pairs, so its a 18 pole. on a 78 GS750

[Grimly]

Yep, so somebody's quite understandably upgraded it.