Stator failures

[gbranche]

On the recent CROV gathering in Kingman, we had two stators fail out of the five Visions that attended. That's a 40% failure rate. Both failures occurred after a high-speed (75 MPH), long distance (98 miles) run at the end of a long day of riding (335 miles total). Being a software engineer, I'm fairly good at seeing patterns, and I'm beginning to see one here. In an attempt to identify a trend, I thought that those that made the trip (both those that had the stator failure, and those that didn't) could provide some details that may help identify the root cause of the stator failures that we all seem to experience. If there's anybody else with any relevant data (not anecdotal, please), feel free to contribute.

What brand of stator do/did you have installed? (Yamaha, Electrex, Ricks, etc.)

How long has the stator been in service? (time/miles)

Have you relocated your voltage regulator?

What type of engine oil do you use? (synthetic/dino? brand? weight?)

What position does the needle on your temp gauge normally occupy on a sustained ride such as this?

There are probably some other questions that should be answered to add to the collective knowledge of this topic, but I can't think of them at the moment. This will be a good start, though.

Greg

[fiddlesticks]

When mine went it was a yammyhammy OEM. I think it was around 12k. Consequently It was replaced with another used OEM. NOt 100%sure because Squid bought my bike,but I think this one has gone south too.
The regulator was not relocated at the time of the first faliure, but he may have moved it afterwards.(maybe he'll post and let us know)
I was running semisynthetic.
Temp needle was normally around the middle after decent ride.

[MotorPlow]

When I 1st got my bike running after I bought it, the Stator needed to be replaced. I bought a used one from another make and model from eBay. ?It has served me well for almost 10K miles thus far. ?The R/R is still located under the battery box in the stock position. I have used Castrol Semi-Synthetic 20W50 oil in the past 2 oil changes (last oil change just this week). My temperature gauge usually rides just left of center.

I also have an oil pressure guage, Thermometer, and digital voltmeter installed on the bike. The oil pressure runs about 65psi when the engine is cold. After warm up, at high speed/high idle the pressure runs at about 60psi, then down to about 5psi at idle. The psi sweeps between 20psi and 60psi during normal riding.

My battery charges pretty steadily at 13.9v at most any RPM, except idle where it charges at 12.5v. ?With the engine off, the voltage at the battery will read 13v+/- and slowly drop to 11.9v, where it stays until the bike is started again.

With the thermometer and the voltmeter on the bike, I have noticed that the warmer the outside temperature, the higher the voltage at the battery when the bike is running and the lower the temperature the lower the voltage at the battery. ?For example, on the perfect riding day (80^o) the bike will charge right at 13.9v. ?Above 90^o and the bike will start to charge at 14.0v, 14.3v, 14.4v. ?The highest I've seen it was 15v. ?Along with this, the lower the outside temperature, the lower the bike will charge at the battery. ?Lately, I have been riding in 40^o and 50^o weather. ?The bike have been reading 13.8v and 13.7v at the battery. ?No matter what the temperature, the charging system tries to get back to 13.9v, but depending on what the outside temperature is will depend on which way the volts will spike (higher or lower).

Does this help at all?

Chris F.

[Lucky]

the ones that failed on your trip, what mods were done?
i haven't had a problem since i moved the R/R & soldered it, before that i burned thru 3 stators & 4 R/R's.

[Ron_McCoy]

I've owned my Vision since new and I'm on my third stator.  The first one failed at approximately 8000 miles and 90 miles from home( up on Sherman Pass road. the CROV guys know where that is).  The connectors were
badly melted so I soldered the connections. The
replacement was an OEM ($ 118) and it went out at about 23,000 miles. At this point I installed an Electrex stator and moved the RR to a position under the lower triple clamp.  This one is still going strong after 3 1/2 years and
over 14,000 miles.  I have used Valvoline 20W50 since the bike was new.  My temperature gauge runs straiaght up on a run like the one Sunday.  It runs higher, maybe 3/4
in 100 degree conditions which is all summer
here.  In 100 degree stop and go traffic it runs almost to the red zone.  One other factor that may be relevant is that I have the higher Euro-
gearing installed as does Rick. Also for the last 8000 miles or so my RR has been moounted inside the nose of the fairing.  Its away from any heat source, but has no air ducted over it.
We were the only two-up Vision on the ride so we were probably running at higher throttle openings at any given time and especially on the grades.

[Rick G]

I believe the reason that  the G7 stator fails in the Vision  with fair regularity  has little to do with the type of oil , RR location  or soldered wires (although all these  have a small effect on the problem .  I did some oil temp tests in OR.  and on a 106. deg. (F) day , running the bike very hard  , climbing in to the Cascades  , recorded  an oil temp of  248 deg. (f)    a H-D  on the same day  had temps of 215 deg. (f) . I wonder what it is here in AZ on a118 deg.(F) day!

As a HVAC tech  I understand heat migration. Heat goes "down hill"  from a hot place to a cooler place.
The oil is supposed to absorb heat  generated  by the stator  and carry it away .
However since the oil is hotter than the stator , heat is added to the stator , causing it to over heat and turn brown , then black, then charcoal.
The eletrex I installed in 2003 was brown when I removed the cover  during my engine "rebuild"  The  stator that was in the engine I used  during the "rebuild"  had a nearly new stator that appeared  to  be a genuine YIC. 
It all boils down to an oil cooler ! Thanks Lucky, I'm working on mine now. 

[h2olawyer]

My original stator lasted 22 years (but only about 6500 miles). ?Last year, I replaced it with a Rick's. ?It lasted 13 months & 1200 miles. ?Installed an Electrosport this summer & have 2200 miles on it so far. ?Bike rarely sees speeds over 65 ~ 70 MPH. ?The original R/R tested fine but I replaced it with an identical type OEM R/R when I installed the Rick's stator in 2004. ?It is still doing great & I carry the original with me as a spare, along with a spare TCI unit.

Until last summer, I always used Yamalube 20-40 dino oil. ?Switched to Bel-Ray EXS full synthetic (0W-40) after changing the stator. ?Great stuff but too much $$. ?Filled with Silkolene semi-synth (20w-50) ?for the winter storage & again this spring after the Rick's stator fried. ?Latest change was to Bel-Ray semi- synth (10w-40). ?Runs noticeably cooler with 40 top weight oil than it does with 50.

Charging is always between 14 & 14.5V in all temps (35F to 105F). ?The bike temp runs at about 3/4 to the warm side of middle when air temps are over 80F. ?If I run the fan, it stays closer to (but still above)1/2 in those temps, even in traffic. ?If air temp is below 80F, I don't need to run the fan & temp stays about mid range on the gauge (needle vertical) at all times.

My R/R has not been relocated. ?I have added a CPU cooling fan to it, though. ?While my Radio Shack thermometer / clock / voltmeter was working, I tested the temps down in the fins of the R/R & as I recall, it never exceeded 110F - even in 100F+ weather. ?That was before installing the CPU fan.

Both times my stator died were after doing the carb synch. ?Idling, heating until the fan runs, in a well ventilated garage. ?Was trying to get it exact & seeing what effects various RPMs (1300 ~ 2500 RPM) had on the synch. ?I'm guessing the oil doesn't move as fast @ idle & heats up more, thus further reducing its ability to cool the stator. ?(Just a thought.)

Current Electrosport stator & OEM type R/R are working well. ?(Knocking on wood here!) ?Checked the carb synch recently & stator survived this time. ?Headlight doesn't dim or brighten with RPMs. ?Cooling fan drops charging to about 13V for a few seconds & then it goes back up to a little over 14V with the fan still running. ?The turn signals & brake lights also move the voltmeter about 1V lower.

When I recently fixed my oil leak (always have to do that left cover job twice to get it right ?::) ) I noticed the pretty blue Electrosport epoxy coating had turned dark brown (after 1700 miles) - but no signs of crispy charring like the original & the Rick's both had.

Don't know if this helps but figured I'd give input as to when my stators failed & what the circumstances were, along with how the charging system operates in normal riding conditions & the oil history.

H2O

[George R. Young]

However since the oil is hotter than the stator , heat is added to the stator , causing it to over heat and turn brown , then black, then charcoal.

I agree the problem is overheating. I had 3 stator failures, about every 5 yrs/25000 km.

However, regardless of the oil temperature, the heat generated in the stator due to current flow has to go out, so the wire temperature rises until the heat generated flows out to the oil. It's this temperature rise that causes the wire insulation to carmelize.

[Superfly]

I do enjoy a good stator conversation (yeah.. you can tell I own a vision or two!) and I have had 2 go out on me within the last few months (one in a engine I just rebuilt, and one in the blue bike)? I still have my Ricks stator (somewhere over 25k on that stator) in a engine I am fixing that is still on my garage floor.? I still think that electricity is frying these stators, and with the one with over 25k on it, I used that bike as a commuting bike.? Typically 85-95mph traveling speed, for extend amounts of time (at least the first 33 miles of riding) and then I would hit some traffic that would drop my speed down to 45-65 mph.? and did not hit stop & go traffic until the last 5 miles of the commute.? I am thinking that helped out alot, plus running an extra ground wire from the RR to the harness.

On the stator that just went out in the rebuilt engine, The stator looks like the charcoal/ fried stator we have all removed from a bike.? My question is that I can see how the hot oil could fry up some epoxy, but how would that effect the 16ga copper wire??

I think that a bad ground, so there is no place for the excess voltage to be dumped could do that.? If the RR has no place to send out the excess voltage, could it be possible that it fries the RR and in turn causes a "backup" of voltage that would fry the stator?

Just some random thoughts before I go to Ricks website to buy another Stator... ;D

Melting point for copper       - 1984.32 ?F
Melting point for Aluminum   - 1220.58 ?F

[Ron_McCoy]

When I replaced my first stator, I ran a
ground wire from the RR to the battery as
well. 

Ron

[Lead_Deficiency]

I was wondering if when a battery begins to fail, does it cause the stator and R/R to work harder causing them to fail as well?

[Junior]

My odd ball V. I put in a Ricks stator and used the old R/R as it checked ok with multi-meter, and useing Luckys info soldered the leads ( I did use a larger wire to the R/R) and mounted the R/R on left rear of bike. Followed Luckys info mostly. Installed a ditigal voltage gage, and this is where it gets strange. This bike did the opposite of other posts on forum. At slow idle (where the engine would barely run), it put out 14.1 to 14.6 volts. Anything above 1800 rpm it put out 13.3 to 13.6 volts. The bike has had  14,000 miles put on it  and has never had another problem. This is in a hot enviorment. North Texas and we have not had any rain fall in my zip code area since June of this year. Now, I have no logical  thing as to why this V ran this way. I have sold it to another rider and he has had no electrical problems. I have always wondered why, as I thought I followed the forums advice closely while doing repairs. Perhaps dumb luck more than anything, but I am wondering if some of the stators are burning up because of too much voltage output. I am sure their are some high techs out there on forum that can shoot holes in this approach, but the bike is approaching 15000 miles on repair and still going. ( Lucky, it is not pink with a drum either)

[glennw]

Greg, maybe you could set this up as a poll?
Just a thought..

3 1/2 years, 6400 miles, Electrex, Soldered wires, Regulator moved to rear peg mount, Valvoline 40w racing oil changed every 6 months or 2000 miles.? Normal temp , dead center. Lost in traffic this past week end... right on the "P" in TEMP

Glenn W
STATOR BURNOUT VICTIM.....

[VisionMeister]

My stator had lasted about 10 years. Was last replaced in 1994 with a Yamaha factory part. It lasted about 10-12k miles (est.)
I had not done any modifications until just prior to the CROV ride. I relocated the r/r to the rear left peg area.
Oil type has varied but I have been using Mobil One Synthetic 0-40w for the last year which I am very happy with (use it in my Ducati 900 with positive results).
My V runs hot. Needle always with 1/8" of red zone. It used to bury itself until I cleaned connections to heat sensors which brought it back to the normal range.