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Stator Cooling - The Final Solution??

Started by Cdnlouie, August 08, 2006, 01:34:10 PM

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Cdnlouie

Most of us have agreed with the diagnosis that burning out stators is an issue of overheating.  We have discussed where that overheating occurs, electrical connections, R/R, engine oil temps, etc. There are many related issues that have been solved here in the discussion of this topic.  But we all know that none of the issues directly provide the solution.

I believe that progress has been made toward the answer even recently with Lucky's oil cooler to address the issue.  Nevertheless, the problem still remains of getting oil to the stator.  It is isolated from engine oil due to engine design, therefore oil does not cover it to provide the necessary cooling effect.

I would like to bring up the "drilled crankshaft bolt" solution metioned some years ago by George Young and others.  George is the only one who actually tried this fix (that I am aware of) and I am curious if there are some results.  This is a fix employed by Yamaha on their Ventures back in 84 as they had trouble with burning out stators.  I have a Venture myself and looked over this fix to see how it works.  I believe Jason has mentioned this at some time in the past as well. The Venture has a very small hole and it really pumps out the oil into a reservoir in the left engine case and then splashes it back over the inside of the rotor.

It seems the Venture uses a washer with the drilled bolt to hold back the oil in a reservoir and then allows the crankshaft bolt to hit the oil as it escapes the chamber and sling it back over the inside of the flywheel rotor (as near as I can see).  The Vision could use this method as well with the addition of a small washer to control the escape path of the oil.  There have been statistics posted here on oil temp and stator temp and the oil is generally much cooler than the stator by maybe as much as 100 degrees F (don't take my word for those numbers). This being the case and many other machines using the same stator but lasting much longer, most likely points to the necessity of solving the Vision engine design problem by getting oil on the stator for cooling.

Now, I am on my third stator and got 15,000 km  (or 9000 mi) on the first and about the same on the Rick's replacement (4 years of running for the last one).  Both stators ended their lives tragically after some hot runs on hot days or long rides. They will be fondly remembered.  The flaming of a stator is a cumulative effect so you cannot necessarily connect it to the events of your last usage, but often you can see the straw that broke the camels back. If your stator goes longer you are lucky, most of us are not.

R/R's can cause issues but they are not the culprit.  Each time I burn a stator the R/R has been totally fine.  I have changed it but there is nothing wrong with it when hooked up, therefore the R/R demons are probably not there.  Again, many bikes use our R/R and they don't experience the same degree of problem.

Soo.... I am looking into drilling a bolt, but need to find the specs George used and some info on how much oil pressure we can spare on the Vision.  If anyone else is interested in the "trial by error' give me a shout.  This could be the last frontier of exploration before we all just accept the inevitable fact of our Vision's lot in life.  It has become a "baptism of fire" that you are not a true Vision owner unless you experienced the burning of a stator.  Imagine what life would be like if a Vision stator actually lasted.

My appreciation to many good comments made over the years as I have read them attentively and they provide the evidence of the problem.  There is nothing new to know about our Visions, but there is something that has conveniently eluded us on this stator issue.  My recent brooding over a totally crisp stator reminded me that we need to throw a little olive oil in the pan to keep things from burning when we crank up these Visions.

Cheers to all!

Louie  ;) 


Night Vision

well, as luck would have it, I may be able to give some insight on how well the oil cooler is helping the stator.

my pesky little oil drip is morphing into a 50 cent puddle and I've had enough. I'm going to pull the cover tonight, install the cometic gasket and reseal the grommets.

I put close to 3,000 miles on since May 1 so the stator should be completely baptized.. I'll let you know.
if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

Extent

We do still get burned stators and each time I wonder exactly what mods has that person done.  I stupidly ignored the prevailing advice of the forum when I first got my V and it wasn't long before I had a burned stator and R/R to deal with.  Immidiately after I went though the soldering and relocating process and for the better part of 10k miles (since rougly Oct. '04) my charging system has been fine. 

So have other people that have relocated their R/Rs had stator failures?  What about soldered connections?  CPU fans?  It's hard to judge what has been effective since whenever someone gets a burned stator they either seem to be running an unmodified system, or they don't mention which mods have been done.  Knowing statistically what helps can narrow down the most effective solution, and could stop us from continuing to stab in the dark after an effective solution has actually already been found.

Comming back to the oil squirter idea though :p I always wondered why not come in from the outside?  Drill in through the side case on the inside of the stator, and place a squirter there, then run hardlines along the outside, like maybe hard brakelines from a car.  That way you completely avoid the flywheel and you don't have to modify any of the internal oiling systems.  You could feed off the oil pressure sensor port on the bottom, or even better if you're running an oil cooler you could feed off the return line.
Rider1>No wonder, the Daytona has very sharp steering and aggressive geometry.  It's a very difficult bike for a new rider.
Rider2>Well it has different geometry now.

Night Vision

Quote from: Night Vision on August 08, 2006, 02:17:07 PM
well, as luck would have it, I may be able to give some insight on how well the oil cooler is helping the stator.

well, my luck sucks.... I'm not going to be able to dive into the oil leak / stator peek-a-boo until I find out why I'm not charging  >:(

rode to work today.... SmokeBomb was running a little funny.. didn't think much of it... spent the day thinking I was going to go after the case leak when I got home....
rode home... felt kinda sluggish  ??? was the headwind that strong?....nope....

I'm not charging  :'( :'( :'(
I've had times when the system wasn't charging at my normal 14.6 at idle... but then after shutting it off, or later on it would come back to normal..funny... I can tell when the bike wasn't charging just by the way it ran

the R&R (relocated) on the peg was friggin hot to the touch too... I should have checked how hot it was when it was charging normal.... but this was HOT

time to snip and trouble shoot... hope I can sort it out before OnRov on Saturday... I have a spare from deck bike... it does work...but the backside is cracked by the wires and I was only going to use it for trouble shooting.. 

if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

Lucky

i'm going to go in reverse order here.

Night Vision, if it seemed to not charge occasionally after riding, stopping, riding, stopping, etc, you may want to look at the kill or ignition switches, or somewhere in a similar circuit..

Extent, i've studied the oil system pretty extensivley, & one thing is for sure, you cannot tap off any section of the oil sysytem for spalsh cooling except at the end of the system where it would splash into the pan anyway. that may well be the crank bolt (do we even know if the crank is properly drilled for this? i'll have to find & check my notes...) so it may as well be internal...

canadianlouie, since soldering & relocating my R/R i haven't had a problem, & the oil cooler came later. unfortunatly i don't really keep track of milage, & don't really have a memory for it anyway, so i can't tell you how long it's been on, but it's been something like 4 or 5 years since my last burned stator.

i can tell you, since you were asking about oil pressures, pre cooler, & on dino juice, on a hot day the oil pressure would drop as low as 10 psi when the oil was beat up & ready to be changed (& i seriously beat up the oil, i will normally run thru a set of twisties at 7-9K rpm)  with the oil cooler & synthetic blend, my oil pressure only drops to about 22psi when the oil is old.

normally on an average day on a 20 mile run to work, my oil pressure ranges between 40-60 psi. 60 psi is the dumpback point according to the manual, & mine actually dumps back at about 58 psi  idling at a light it never really gets below 30 psi.

hth, --Lucky
1982/3 XZ550 Touring Vison, Gold on Black

Night Vision

Quote from: Lucky on August 08, 2006, 11:00:08 PM
Night Vision, if it seemed to not charge occasionally after riding, stopping, riding, stopping, etc, you may want to look at the kill or ignition switches, or somewhere in a similar circuit..

don't mean to veer the thread, and I will get to fixing the oil leak / take a look at the stator and report back....

                    ..... but it's more like....

works great for weeks/months... bites once in awhile... I check it at least once a week

check this out and see what you think....
was not fully charging tonight, probably this morning too. got home... reading right around 12.5 volts... bike running rough like I said... headlight dim... volts slowly going down to 12.3

unhooked battery, hooked back up... same thing 12.3v..
took battery out and put in on trickle... jumper cabled leads to spare car battery.... she's pumping close to 13.5 back into big battery and going higher!!! WTF ?
Put vision battery back in... she's charging back up again... take her out for 20 miles.. runs great... charging fine. I just went out and started it... climbs back up to 14.7 like usual..

It almost seems like it needs to be "reset". without snipping the wires, I can't run the fault chart, but my gut feeling is that the regulator needs to be recified

if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

Cdnlouie

Extent, I considered the same exterior option when I first looked, but as Lucky has described, it makes more sense to use the internal oil passage path if it is available and it is there.

Fortunately, the oil path does go through the crankshaft since the starter clutch gear requires lubrication from a pressure feed and the flywheel bolt seals off the end of the passage (there is a hole in the crankshaft and a brass bearing with oil passages in the starter clutch gear to hold the pressure). Now, I would want to confirm that is pressure fed, but I can't imagine that design not being pressure fed, however, something to confirm. I would be interested in another view on that point. I am not sure if the manual tells us that detail.

Therefore, we have an (assumed) internal feed that just needs to be directed through the bolt and into an appropriate reservoir so that it will be picked up by the bolt head and transferred back into the flywheel where it should provide an oil bath for the stator.  At the moment, the stator is virtually oil free since it is completely covered by the flywheel and the oil level is way below the flywheel.  This is very similar to the XVZ1200 which to aid cooling, Yamaha drilled the bolt and provided a washer to hold the oil back until it could be picked up by the crankshaft bolt head and flung inside.

It is hard to determine how the oil acts when it goes into the flywheel but at least it would be bringing oil into contact wiith the stator and allowing some cooling effect to take place.

The risk factor is diverting too much oil from the system.  In other words, how big can we make the hole assuming the bearings and top end can handle the slight decrease. It may be that an oil pressure test before and after will give some idea of the bleed off effect an extra orifice will provide.

As I mentioned earlier, George Young did this several years ago but he sold his Vision in 2003. I send an email to him to see if he sold it modified and if it is still around and the size of the orifice he drilled.

The oil cooler idea would really have a serious effect on the stator cooling if we could get the oil to the stator.  At the moment I am sure that it is helpful but maybe not as effective as it could be.

I will mention that I have done all the modifications years ago (4-5) and the stator lasted only this long.  I did have a battery go bad during that time which could have had an adverse effect, but I do not think most of what we have modified seriously effects the stator life.  At least not more that chance favors us all (at least some of us, some of the time).

Something to think about anyway,

Louie  :-\


Lucky

Night Vision, it does sound either like a battery with an intermitant cell (disconnecting internaly) or poss an R/R problem.

the question, is how do you load test a motorcycle battery? i have a carbon pile resistor load tester for automotive batterys, but i'm not sure if it applies to bike batteries. this needs to be reserched, and to properly do the tests, the battery has to be good (so it has to be tested first..) 


--Lucky
1982/3 XZ550 Touring Vison, Gold on Black

Night Vision

battery was my first gut feeling and I was about to go to Wally World, but after I put the battery back in and it was charging, I didn't. It's an interstate with 3.5 mnths / 3000 mies on it.

I did not know you can have an intermittant dead cell. I don't have a way of load testing it. I do have an old style battery cell analyzer that shows the strength between cells. It'll show if a cell is dead or weak. Problem is the battery is sealed by the flush cap seal strip and I'm not sure if I want to crack into it just yet.

hopefully, she'll not act up again untill after this coming Monday  :D In the mean time, I'm looking for a good (spare? or replacement?) R&R. Just might get the Wally Batt too so I have a spare.
if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

supervision

 I guess I was under the impression that if oil was cooled down we won't cook the stator.
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George R. Young

The bolt specs I used are here
http://www.ncf.ca/~ag136/bolt.jpg
It was not conclusive. I made this modification about half way through my 3rd stator, and it failed also.

I've never tried this, but perhaps the solution is to use wire with a coating that can withstand the temperature, instead of the varnish and paint approach. A Vision dream, a stator wound with teflon-insulated wire, and let it heat.

Lucky

Night Vision,
just an FYI, so you understand a bit more about battery construction:

simplified:
-the battery has 6 cells each, of 2 volts (12 V total)
-each cell is made up of a positive & negitive plate.
-all the positive plates are connected to each other by strips of metal, as are all the negative.
-the strips are soldered to each plate & 'hopscotch' over the opposet polarity plate it's next to.

when the battery is 'under load' that is stressed by a high sudden discharge, such as starting the bike, this can cause the plates/strips to get warm, & heat deforms metal (fatigues it after enough cycles), the solder joints between the strips can weaken (the bikes vibration adds to that) and can cause the electrical connection in the battery to be broken temporrarily, especially under load.

a carbon pile resistor, or 'load tester' creates a controlled short circuit across the battery terminals, 'testing ' the battery.  if the voltage of the battery drops below a certain point durring the test, or drops to zero immediatly, the battery is toast.

testing specific cells with the bulb tube tester checks the battery acid's specific gravity of each cell, & is not the test i mentioned earlier.

hope this clears up some confusion.

--Lucky
1982/3 XZ550 Touring Vison, Gold on Black

Night Vision

ya lost me on the load tester, but the intermittent dead cell makes sense.

What I have is not a (bulb jobber) specific gravity tester...

it's a cell analyzer with pos and neg leads that measures volts between the eletrolite (you can't tough the plates with the leads) between cells. it ranges between 0-0.4 volts (dead cell),  0.4-1.6v (discharged), and 1.6-2.2v (charged).

the instructions on the meter say turn headlights on for 1 min. , test with headlights off.
if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano

Lucky

well the load rester does basicly the same thing as turning on the headlight, just more powerfully..cranking the starter with the plug wires removed would be a suitable test, just make sure the meter is hooked up so you can see it. if the voltage drops below 9.5 the battery is on it's way out, or you have charging system issues.  recharge the battery & do the electrex test.
1982/3 XZ550 Touring Vison, Gold on Black

Paul_Jungnitsch

My last stator went 50,000 km plus on a totally unmodified system, so who knows? Tho' I lean towards the poor ground on the regulator idea. My bike was an oily one, wouldn't have been a lot of corrosion happening.

One interesting thing would be to put a temperature sensor directly on the stator so an eye could be kept on actual stator temp.


NewVisionGuy

I asked the previous owner of my bike  and he told me that over the  10,000? he'd ridden the bike,  he checked  every connector on the bike regularly and used  dielectric grease in and around the connectors, and never had a stator go out.   He bought the bike new in '84 as a leftover  after some lady  pulled out in front of him while he was on his first V.   But  this  may be  just  overwhelming luck...    Lucky  even tells new vision owners to  clean up all of the connectors on  their bikes and he's had a stator burn out.
but who knows...   keeping the connectors clean would definitely help.

Lead_Deficiency



BlueBass - everytime I read a posting of yours I keep hearing Shaggy in my head  :P  :D

dpequip

A little food for thought.....I am new here but old to Visions.  I've owned one since 1983 when I was employed at a Yamaha dealer during college.  Early to mid 80's Yamaha V engines with oil cooled stators (Vision, Virago, Venture) have known stator failure issues.  The issues became pronounced on the Ventures due to the much higher amp loading and all the lights and stuff dresser riders put on their bikes.  At one point we were replacing stators in Ventures every few thousand miles before a final fix was affected.  The Venture fix was a new Stator coil with upgraded insulation (Epoxy  type), Drilled rotor bolt, defector piece, and a piece of wire that acted as a scraper inside the bolt.  The drilled bolt is to allow additional oil to reach the stator coil and cool it.  The deflector is to direct the oil towards the top of the stator coil.  Most failed stator coils in my experience are burned at the top where oil is least likely to splash up there.  There was also a wire scraper that went inside to bolt to prevent the hole in the end from getting plugged up.  I do not remember what the size of the bleed hole was but it has to be very small to prevent excessive loss of oil pressure to the crankshaft and rod bearings.  To my knowledge these mods fixed the Venture problems.  Visions and Viragos had fewer stator failures because the electrical systems on these bikes were not required to put out the amps the Venture needed.  I have had one Vision stator failure @ 17K and that was after a 700 mile ride on a really hot summer day.  I would agree that long rides on hot days contribute to stator failures.  The effect of heat is cumulative on the stator.  I don't think oil coolers will help that much because the problem is a lack of oil splash on the upper part of the stator coil.  The cooling of the vision stator coil is dependant upon the oil splashed on it by the rotor while it is running.  If I remember correctly some time around '84 Yamaha improved/changed the insulation on all the oil cooled stators to improve service life.  This included production bikes as well as service parts.  Seems like I remember discussing this with the Yamaha service rep at the time and his comment was the improved insulation would take care of the problem on Visions and Viragos. 
1982 Yamaha Vision Owned Since New.
Mods:Euro Primary Gear set, Euro footpegs & controls, Yamaha 1/4 Fairing, Braided Stainless lines, Forkbrace, Tapered roller bearings in steering, '83 rear Shock

Walt_M.

Very interesting reading dequip. About a year ago, I bought one of the improved insulation Yamaha stators on ebay. I have yet to use it as my original is still going ok. The bike has only about 15K on it.
Whale oil beef hooked!

Night Vision

Lucky, can you explain to me why won't Extent's idea of tapping off the oil cooler return line and squirting directly onto the top of the stator won't work  ???

seems to me if your motor didn't grenade when the oil pressure dropped to 10 psi when oil was hot and old, and now it's 22 with a cooled syn blend, can there be much harm in sharing a couple of those pounds?

After seeing the difference between synthetic and dino oil temps this weekend, I'll definitely be going to syn or a blend. drive shaft lube also.

Why can't ya tap a bit of flow off the return line, tap a line into case, use a heavier synthetic (say a 20-50) and squirt some love on the stator?



if it ain't worth doing it the hard way....
it ain't worth doing it at all - Man Law
;D


if it ain't broke..... take it apart and find out why


don't give up.... don't ever give up - Jimmy Valvano