Picture of Rebuild your bike's expensive stator
Here is how I've rebuilt the stator of my bike, a Yamaha yp250 scooter, branded here in Italy as Majesty 250. It might be also valid for other brands.
The original part is WAY too expensive here (more than 600$), so I HAD to invent ways to solve the problem. I drove the bike using this rebuilt stator for about 600 miles now and its still working. Im not sure that the insulating paint I've used will stand the eat from the engine motor oil as the original.
So far so good....
Step 5 has a picture with the complete schematic of the wiring.

Suggestions and criticism are welcome.

Step 1: Original stator.

Picture of Original stator.
This is the original faulty stator. It has all of its 3 windings shorted to the metal body.

Step 2: Uncoiling the thing

This is a quite tedious job, as the epoxy is quite hard to remove. You might need the help of a screwdriver to lift up the wire inside and between the poles. Be careful while handling the copper wire as you unwind it. Some of its insulating paint bits, still attached, are sharp and might cut your skin.

Step 3: Preparing the support

Before recoiling the stator, make sure to prepare its surface, smoothing out with a file (or a minidrill) all the sharp edges. In my case this step was absolutely required as I mistakenly removed the epoxy residuals (as you can see in the first picture below) with a paint removal gel. I had to prepare 36 small pieces of mylar cardboards (same used in transformers windings) cut in right size and cover with them all the poles.
Remove these adsRemove these ads by Signing Up
1-40 of 46Next »
jbest44 months ago

how far have you ridden now and is it still working like a champ?

jlilbrother10 months ago
I have to give you mad props for even attempting to do that job. I guess I should count myself lucky, the stator for my bike is only $65. But seriously, fantastic job man.
undinstructable (author)  jlilbrother10 months ago
Thanks, man. Always a pleasure to get positive comments! Glad if it was of help to you
wanwnp2 years ago
nice tutorial!
very good on the warnings included, ie rough edges, etc..

however i wonder whether the cardboard melts inside your engine oil or not...

anyways, i think i wanna try your method, probably i can help others and earn some money out of it.. the shops that provide rewindings here are expensive!
undinstructable (author)  wanwnp2 years ago
Hi Wanwnp.
Actually the one described here is my first attempt. it worked for a while before a short made necessary to wind another one. This time though, instead of using the cardboard (which by the way is a special type made for transformers, and wont melt in hot oil) I cover the sharp edges with double component epoxy glue, my one stand 300° C, It is sometime called liquid metal. The stator is still working in my bike since I've built it this way.
danzar2 years ago
Very nice.
warar33 years ago
hey when connecting the wires to the regulator do they have to be in order
they goto the rectifier
undinstructable (author)  warar33 years ago
No, they don't have to be in order, you can connect to the regulator in wichever order you like.
Good luck!
Hi i havent been able to find any epoxy type paint any ideas i live in a kinda small town i got some hardware stores and some major ones like lowes/ home depo
undinstructable (author)  warar33 years ago
Hi there.
I don't know where do you live, but, in the States something quite popular is a product called JB-Weld:

I have used that in a second version Ive made, as the first one got shorted because the sharp edges of the metal core. Ive used the glue on the core to smooth the edges and on the wires at the end to seal the whole thing to get something similar to what you can see in the pictures of the original stator.

one more thing you said you dipped the whole thing in the ins. paint and then in the oven. what about the top/surface metal dose that have to be sanded down for or did you just leve it // the very out side top with little metal lines//

thank you SL
undinstructable (author)  warar33 years ago
you dip the whole thing in the paint, then put in the oven. This shold be done a couple of times, for additional insulation. I suggest to have it done by a professional rebuilder like an electric transformer repair shop... Since the cooking is a rather long process, they do in batches, when they have several transformers or devices ready to be treated.
actionman723 years ago
Wonder, wonderful article, friend! People like you make do-it-yourself repairs a pleasure. If I had a spare daughter, I would give her to you.
I just rewound my 95 Bayou 300 4x4 stator using your guide. WOrked like a dream. Good stuff!
undinstructable (author)  actionman723 years ago
I'm glad my instructable helped you.
Pity you don't have a spare daughter! ;-)

MatrixRage4 years ago
You sir, are a freaking genious. Great instructable, very clear to read, great diagram at the end of the article. thanks
jimjutte4 years ago
Your article goes well beyond what I was looking for, but certainly gives me something to think about for the future. I have a Majesty 400. At the risk of asking a stupid question... because I did something stupid.... the wires that come off of the stator and go into a connector... is there a particular order that they MUST go into the connector. I wasn't paying attention while moving my bike and somehow manage to pull the connector plastic off of the three wires... now, I don't know the order that they need to go back in. :( Cheers
undinstructable (author)  jimjutte4 years ago
Your question is actually very pertinent, :-) especially if you're not into electronics. The order the wires are in the plastic connector doesn't matter, so you can insert the wires in whichever order you like. Make sure the voltage regulator is okay, also. It should have a connector with 3 plus 2 contacts, the 3 on one side and the 2 at the corners at the opposite side. The 2 contacts are where the + and - comes from. The 3 contact on one side is where the actual wires from stator go and this is the "input" side of the regulator. Have fun
Thanks very much. Indeed there are two others, a white and red. Thankfully, they were part of a separate connector. Cheers
hectortito4 years ago
is there a machine coiling ? For this case
undinstructable (author)  hectortito4 years ago
Well, I think there is a machine, but not where I live or not that I know about...
That's why I had to do by hand! Also its cheaper.
shteef4 years ago
 great ible mate, the stator on my outboard motor is buggered and Mercury want $639 for a new one!! i will be following your instructions Very closely this weekend.
undinstructable (author)  shteef4 years ago
No problem man,
Just  a few tips:
Make sure to file or sandpaper the edges as its very easy to scratch the wire enamel and short the winding.
I've used a bit of heat resistant metal epoxy, standing up to 230 F°,because my stator works submersed in the motor oil, . The epoxy  makes edges rounder and lessen the occurrence of a short.
Check anyway with a multimeter after each pole is completed.
Here's a very handy web page about motor winding for electric powered airplane models:
Have fun and good luck!
Dr.Bill5 years ago
A star wound generator. You have given me an idea! What kind of amperage does this thing put out? At what voltage?
undinstructable (author)  Dr.Bill5 years ago
Can't remember what amperage is the thing, now. But it would provide enough for battery charging and services, (e.g. lamps, horns) Hope it was helpful. Cheers- A
I need enough power to runHam equipment so I guess if it charges batts it'll be ok. Thank you.
most tri-pole cycle stators usually can put out 200+ Watts  @ approx 13.5 volts
JerryMopar4 years ago
WOW, very simply done/very effective 'ible. Maybe Ill try this when/if I even fry one of my cycle's stators. VERY well done my friend!
undinstructable (author)  JerryMopar4 years ago
Thanks Jerry....It was tough, but it worked at the end! And very rewarding!
mattccc4 years ago
can i have some meserments of the stator
Adri_665 years ago
Very good guide, I have understood everything! Good job
undinstructable (author)  Adri_665 years ago
Thanks Adri. Hope this will help repair you bike or whatever it is! Have a nice day. A
vespatim6 years ago
Great instructable! I was wondering if there was an easy way to test if a stator will work before installing it using a multimeter.
undinstructable (author)  vespatim6 years ago
Of course there is a way, but it is not always practical, especially if the windings are under a thick layer of resin.... First check) First you should check that none of the three wires coming out of it is shorted to the metal part... Sometimes, especially due to high temperatures involved, the wires lose their insulation, especially on sharp edges, so they short to the metal body of the stator. Put the multimeter in "Diode" mode, the one that buzz when you short the probes, then one probe on the metal body, (make sure the resin is not insulating the probe), the other probe on each of the wires, in turn.... if you got the buzzer buzzing, then the stator is shorted. Second check) Even if the wires are okay respect to the body, the stator could still be faulty because the wires are shorting between them.... As you can see from my diagram, the wires are tied together at one end... To check for this kind of fault, you should untie the wires at the common end and check if each one if electrically insulated from the other two. In both cases, if the stator turns out to be faulty, it must be rewinded, as I've showed in my instructable. I hope this helps you. Ciao
radiorahim6 years ago
Looks like Iron mans chest piece. What's a stator?
undinstructable (author)  radiorahim6 years ago
A stator is something that is static, i.e. doesn't move. In our case, it stays still inside the engine's carter, and magnets spin around it, causing the windings to generate alternate current. You will study it in Phisics when you'll grow up! :-) Cheers.
buhdieboy6 years ago
friendly point is when winding it(stator or house transformer) sometimes helps on certain models to wind wires the same direction as original also count the turns of wire if that are 70 turns on a pole 70 to say 80 go back," dont over wind and certainly dont underwind also the size ? you might go 1 size(gauge) smaller its just that it willeduce the current say 10% im going to guess that the polyurethane wire mite be better for the oil emersed stator ( somebody check this )also when adding more turns expect the voltage to go up perprtionally something like 10% mite equal something like 3 more volts ect also a battery can be charged with more volts proubably as much as 3 x the normal voltage as long as the current doest exceed the ccr the thing here is blowing out light s or solid state stuff like regulators could be relevent also the loaded down condition of the battery and connections could come into play on reliabilty facs make drawings of connections and direction beforhand?
1-40 of 46Next »