New theory of stator failure?

[Cdnlouie]

KB, that is a darn good write up there mate!  You've got to put the great info you have together in one place, while this job is not for the faint of heart, it is definitely an interesting challenge to undertake sometime, with "time" being the key word.

Love the diagram and explanation. You have definitely isolated a key issue in your autopsy about the cause of death.  More fellows should take their stator apart to confirm those findings or isolate other weak points in stator design.  You can know for certain that stator rewinders are not really interested in putting themselves out of business, so building a lifetime stator is not too likely.  Usually the cheapest way to mass produce a stator is the "accepted norm" so advances in insulation improvements are not likely to be high on their list.

I was thinking that it might be a good idea to embed the first layer of wire in a durable epoxy to isolate (and insulate) the wires more securely, rather than just using the finished dip approach (mostly exterior).  As you have pointed out, this zone is more vulnerable to shorting out. Finding the right insulation is something that can be easily changed in this process.

Start racking up some more miles so we can help you celebrate your success.  I think you have the longest lasting record for doing your own stator rebuild, so kudos to Kiwi!  ;)

CDNL

[inanecathode]

I'd imagine saturating the coils with extremely hard and durable (read jb weld) type epoxy would help alot.

Kiwi, you said 15 turns on each pole right? What gauge wire did you use?

[Cdnlouie]

I wonder if powdercoating would work?  ??? Drop the whole stator core off and have it powdercoated then do the windings on top of that. I am not sure about the insulating value of powdercoating as there are a few different types but it certainly provides a good coat and is amazingly durable.

The ceramic process on our MAC pipes would probably be an example of one type.  I have had regular powdercoating done on custom work, but I am not certain of its insulation value.

Just talking out loud here,  ???

[kiwibum]

I'd imagine saturating the coils with extremely hard and durable (read jb weld) type epoxy would help alot.

Kiwi, you said 15 turns on each pole right? What gauge wire did you use?

I think it was 15 (or 18), was a year ago when I did it and didn't write any notes just took photos. Just count them when you unwind the first one. An extra one or couple less wont make that much difference because you are limited to the number you can put on in total anyway due to physical space. I think it's 16 gauge wire and the original was 18. I still have a bunch left over (I bought enough with the aim to do a spare one) but don't have a micrometer to measure it, I'll see if my verniers will be accurate enough.

Regarding jb weld, I'm not convinced that something extremely hard will be the best. Due to thermal expansion copper moves quite a bit so something that is allows some give but is durable may be better.

[inanecathode]

Hmm, some sort of hard yet flexible resin. Like rtv mixed with jb

[kiwibum]

I wonder if powdercoating would work?

CDNL: thank you for your kind words on my instructions, keep that up and I may just get round to writing those how-to's.  Yes powdercoating will work perfectly. That's what got me originally thinking about rewinding and how to insulate it. I was in the shop that serviced my bike for the previous owner and we got talking about stators (they had done at least 3 on this bike). He said they had two guys locally that did the rewinding for them and one used powder coating to which the mechanic then said anecdotally we had less problems and seemed to last longer than the ones the other guy just painted. Only reason I didn't powder coat mine is I was a poor student at the time and the POR15/fiber glass route seemed cheaper. Next one I do I think I'll have powder coated and try the mylar cardboard (or get some 3M fiber glass tape). Main reason I haven't done a spare is the fiber glass cloth method was a little too frustrating and messy for me to bother with it again when the one I have is working fine. I will be doing more though when I rebuild my other two 550's. I've been wondering if I can program my CNC Mill to do the winding for me:-).

inanecathode: Anything resin like is a pain in the * to put on because it drips everywhere and is difficult to keep uniform on the odd shape of the stator, this is why I keep saying I like the idea of the cardboard or 3M tape. If I figure out how to use my Mill to do the winding I'll be using the tape for sure, then putting on resin afterwards to hold everything in place rather than for the insulation between wire and poll.

[treedragon]

Was mentioning this thread to someone in the trade or near enough to, he agrees long life is not a high priority for the rewinders. On the odd occasion he has a stator rewound for himself it is "coated in epoxy and wound with ceramic tape before it sets, then rewound". Says he has had none fail.

[kiwibum]

"coated in epoxy and wound with ceramic tape before it sets, then rewound".

Ceramic tape, that sounds even better than mylar cardboard or fiber glass tape, will definitely handle the heat. Can't find a price online :(
"Nextelâ,,¢ Woven Tapes are made from the same high-quality, continuous alumina-boria-silica fibers that have made 3Mâ,,¢ Nextelâ,,¢ Ceramic Textiles the best solution for high temperature applications. They provide simplicity and dependability at two different high-temperature limits: 2012° F (1100°C), and 2500°F (1370°C)." http://www.3m.com/market/industrial/ceramics/materials/tape.html

[inanecathode]

What about header wrap?

[Lucky]

too thick

[inanecathode]

What's mylar cardboard anyway

[Tanno]

My first dead stator (original equipment @4500 mi.)  I replaced the stator, R/R & battery (sealed maintenance free Interstate).  Stator died after 1,000 miles.  Have replace all again.  This time I went with the Electrosport R/R instead of an OEM type.  Nearing 800 miles so far.  Noticed on my last ride back in November that the R/R would jump up to peg my volt gauge for a second or two (18+ V) and then drop right back to 14.5.

Hopefully, the R/R that's under development through Tanno will cure the ills.

H₂O

Still working on it. Good to see that the hope is still alive!

[Cdnlouie]

I must have a chat with a buddy of mine that works for the Pratt & Whitney manufacturing here in Toronto and ask him about some of their "fancy products" they use in high temp applications for jet engines.  I asked him about some epoxy type resin to recoat any nicks in a used stator winding and he had a terrific recommendation for products the average joe would never get his hands on.  What kind of maximum thickness would be allowable for the insulating material (Kiwibum)?

He is another "off the wall" thought. I am wondering if insulating the stator mounting point as well as the attachment screws would help prolong stator life? If one wire did short out on the steel core but could not short to the engine ground, would it still operate effectively (or well enough)?  At least until one of the other two windings shorted out to the steel core.  The idea being to keep the voltage from going to ground by isolating the stator core.  If that fellow epoxy dipped the whole stator core before rewinding, then he would most likely have also isolated the core from grounding to the mounting case.

Good research and thought-provoking ideas on this topic.  Definitely, one of the closest ideas toward a better stator and hopefully you can test those ideas out Kiwibum. Even if you can try a couple of these new ideas out and get a stator to last 10-15k you can probably sell a few here to help recoup the costs.  I am sure you can even find some volunteers for testing  ;D.

We might even be able to get a deal going with a rewinder to rewind a stator according to our specs once it is proven it works.  A little guy might be more cooperative.  Someone like Tim Parrot (I think that is the fellow) who offers the cheapest stators on ebay. A little dialogue with him might get a higher spec stator available for no more than the big guys and maybe cheaper.  It would not cost him too much to throw a few stator cores in for powercoating and then wind them up.  Or we could prepare the core and sen it to him for rewinding (He is not likely to care as he still gets paid for his work).

Our Vision has a stator overheating problem (no brainer there  :o) that shortens the life of the stators (engine design), and no one else really has the same problem, so no one else is motivated to solve it, or spend more money manufacturing a better stator for the same price.  If the insulation of the core is the biggest issue then it certainly can be solved.  If that actually happened we would probably lose our historic identity as the flaming stator club  ::).

Keep up the good work,

CDNL

[inanecathode]

Isnt it vibration that fails the stator to ground?

[Cdnlouie]

Yes and no, vibration my deliver the death blow, but only after the stator has been cooked by its isolation inside the oven of the flywheel where it receives virtually no cooling and is baked by the radiant heat that accumulates in the flywheel as well as internal temps.  Generally the cooking takes place more toward the top which is probably the hottest zone.  This is certainly speculative but having seen a lot of stator designs over the years it's not hard to imagine that this is very probable and even predictable due to design of putting the stator inside the flywheel rather than outside as in so many earlier designs which never had stator issues.

The Vision is a pretty smooth engine compared to others, therefore I don't think that vibration is the key element. It just delivers the death blow once internal engine heat has deteriorated the stator sufficiently.

[inanecathode]

If you fix the vibration then the heat shouldnt be a problem. How hot does it get under the flywheel, 300 degrees +?

[Rick G]

I can't say for the temp under  the flywheel but my tests on oil temp indicated  a temp under hard riding conditions  in over 100 deg.f ambient  temps., produced an oil temp of 248 deg f. so the engine is probaby much hotter.

[inanecathode]

Think it'd get anywhere near 350 degrees?

[kiwibum]

What kind of maximum thickness would be allowable for the insulating material (Kiwibum)?

I don't think you want to go much thicker that 1mm (0.04 inch) due to needing room to wind the coils on. If the insulation is still breaking down at that a better insulation is needed. I think insulating the whole stator wouldn't be worth the effort, partly because you will have problems with the screw holes lining up and the stator slides onto a cylinder on the side cover to hold it in place so any insulation on the inside of the stator will prevent it fitting in place.

If I get time before I store my bike and figure out the data logger I got I'll tell you exactly how hot the stator gets. I have a temp sensor epoxied to the stator windings in my bike specially to find this out. But it's finding time to get all these things done unfortunately.

[supervision]

 I have noticed that their are many sv650 and dl650 motorcycles, and very little talk of stator failure.  The system is like ours, with the magnet coveering the stator so should experince sim heat.  Maybe just better OEM stator to start with?    Are we just doomed, because we had a inferior piece to start with, and then mainly low quality rewinds for replacements?   or maybe a difference of magnatiziem, or air gap. Maybe these suzki guys figured out a good combo for longjevity, and we haven't got it.  Their are so few VISION'S, by compairison, and all have stator failures, on a regular basis.  What's their secret?   The next time I'm riding, I'm going to touch stator cases of sv650's and see if they are smoking hot.  Just a thought