stator running hot

[glenc44]

My 83 Vision with 23K fried its stator. Let me back up a little. After reading a lot on this site about stator trouble I checked a few things. Measured the side cover temp after a long ride, 230 F. I was worried so I checked all the connectors I could get at. Made sure they were clean and put dielectric grease in them. Went for more rides and decided to see how high a speed I could get on my stock 83 Vision with fairing. Close as I could read the speedo I just made it to 100 mph. On the way home the main fuse burned out. After disconnecting a lot of things the fuse still burned out. Hauled the Vision home in my truck and started taking thing apart. Found burned stator.So I assumed the r/r is toast as well and found a G7 stator and Mosfet r/r. A year later I finally got around to putting things together. Found an extra brow wire on the stock r/r and was not sure what to do with it so went back and checked the original r/r. It checked out in good condition. The fuse still failed even with the r/r disconnected. Removed the whole wire harness and unwrapped all the tape, no short could be seen. Re-wrapped the harness and put it back on, still has a short. Started over at the fuse block and found the first connector on the main power line was internally shorted. It had heated up and melted the the plastic until the plus an minus touched. This blew the fuse and allowed the plastic to cool with the connector still shorted. I broke the plastic away and checked the tightness of each connector when slipping a spade in. Not very tight. I went around the whole harness, removed and tightened every female spade connector. Replaced the melted plastic connector with a good used one. Replaced the starter clutch bolts and lock tight and peened them. Checked the big nut behind the starter clutch, OK. Now I think I have the stator, connectors, and starter clutch fixed. The last thing I did was drill and tap the rotor bolt and installed a .7 pilot jet. I also drilled some drain holes in the side cover around the stator mount so oil would not accumulate. Started the bike and I have 14.5v at idle. Went for a ride and measured the temp on the cover, 190 F. I like the look of a naked bike so I left the fairing off and went or a speed run, 105mph. Then checked the temp again 195 F. I won't claim the lower heat is all due to the oil cooling but it is running cooler and time will tell if the stator will last. Honestly I think the loose fitting connectors are the biggest problem.

[QBS]

Fyi, my '83, with all fairing pieces installed, has red lined the tach in fifth gear many times.  The speedo was reading 120 mph.  V (actually most bike speedos) speedo's aren't very acurrate.  The tach really tells the tale.

Your lowered operating temps are good news.  However, there are two varibles that might be at least partially responsible, ambient air temp at time of engine temp reading and change in fairing configuation.

[Rikugun]

I don't think many would argue excessive temps are the bane of the stator but how to combat the problem continues to be a hit or miss affair. No two Visions are the same as far as fuse type, quality of all connections, stator brand, R/R type, battery type/health, rider style, environmental conditions, accessory load, etc. It's difficult to come up with a fail safe protocol everyone is able and/or willing to follow.

It sounds like you worked through your problem quite satisfactorily and spent some quality time with your V in the process!  :D Those are great tips to try for anyone still struggling to keep a stator alive in their Vision. Just to clarify - was the new lowers temps and 14.5 idle voltage using the original or MOSFET R/R? BTW, the brown is a fused source of system voltage sensing for some R/R's. I don't think MOSFET's require that connection.

Also, what type of fuse block was in use when the melt down occurred? Did you happen to photo document your oil cooling and drainage hole mod?

[cvincer]

You said you drilled & tapped the rotor bolt, then fitted a  .7 jet.

Could you please clarify what you mean by the rotor bolt please.

Thanks

[Jimustanguitar]

You said you drilled & tapped the rotor bolt, then fitted a  .7 jet.

Could you please clarify what you mean by the rotor bolt please.

I'm also curious about the drain holes under the stator mount... Is this procedure documented elsewhere?

[Rikugun]

You said you drilled & tapped the rotor bolt, then fitted a  .7 jet.
Could you please clarify what you mean by the rotor bolt please.
Thanks

Rotor="flywheel"    He has tapped into the oil running through the crankshaft to direct a metered stream of oil onto the stator in an effort to cool it. This is purportedly used in some Yamaha V4 designs and has been tried by several members. The second part involving draining accumulated heated oil through drilled holes may be a novel idea. Inquiring minds want to know more!  :D

[glenc44]

 The bolt picture is attached. I cross drilled a hole to spread the oil around more. The nice thing about the jet is I can remove the cover plate to change the jet size if needed.
The  first temp was checked with the fairing on, and the second temp was checked without the fairing, after I modified the bolt. I did wonder if the fairing affected the temp so after my ride I put the bike on the center stand and ran at 3000 rpm until the cooling fan started. The temp did not change with the fan running. I assume the temp would go up if the coolant temp went up. The oil temp is controlled to some degree by the water cooling.
No picture of the drain holes. If you look at the inside of a cover with the stator removed and imagine where could the oil drain down you can see where holes would help. I drilled 4 holes 1/8 inch in diameter as close to the outside wall as was easy to manage the drill.
My speed was mentioned as a reference for with and without the fairing. I don't think 100 mph is fast for a Vision or any bike for that mater. I know guys racing Ninja 250's at 108 mph, still not fast by any standard but pretty good for a 250 econo sport bike.
This Vision is a work in progress. No particular goal in mind. I just want it to run and will mess with things as I see a reason to do so.
Just for general info about myself I have been roadracing since 1976. My best finish was 10th at an AMA pro 250GP race. I was one of the guys on track that made Rich Oliver look fast.

[glenc44]

Sorry I didn't answer about the fuse block. When the connector failed the original fuse block was on the bike. I tried to tighten the clips on the fuses and 3 of them broke. The replacement block I found at a local auto parts store. The one I used has 5 blade fuses and spade connectors exiting out the side.  The 5th position is not used except to hold a spare fuse.

[pinholenz]

Sorry, I am being a bit slow here! Am I right to say the entire length of the flywheel bolt  is drilled out and then partially tapped The .7 jet then screws in to below where the cross holes are drilled so that the jet is regulating the flow to the cross holes? Thanks

[glenc44]

Pinholenz, you got it correct. I can sometimes be too wordy so I tried to shorten what could be a long, detailed, boring description. I guess long and detailed is what was needed. In the end the bolt head was drilled larger to the point below where the cross hole is, then tapped to the jet thread. Since I wanted the oil to go mostly radially out the cross hole I cleaned the hole and sealed the end hole with blue sealer to just before the jet. The sealer can easily be removed and resealed, if I change the jet. Later year Yamaha Ventures had a wire in the hole to keep it clear. Some owners removed the wire and this caused the oil light to flicker at idle. The Venture also had an oil scraper plate to get the oil off the rotor. I rely on the drain holes and gravity. I could be losing some power from oil drag but not a lot as indicated by the speed run.
To clarify about the r/r. The original r/r was on the bike at the time the stator failed, and because I was uncertain about the function of the brown wire I reinstalled it and checked the charge voltage at idle, 14.5 v  . My hope is this is a good sign the r/r was not damaged.
I think I covered all the questions. If more please ask. If I messed up in description, or repairs, or ideas let me know.

[pinholenz]

Helpful description, thanks.

And I guess the   sealed bolt end will also prevent the jet coming loose as well as ensuring the oil gets distributed out the sides of the bolt.

Can you recall what size drill went right through the bolt? Did you do this with a drill head on a lathe? Cheers.

[glenc44]

I have a friend with a quality lathe and collets. He did the drill and tapping for me. I have a note somewhere with the sizes of all the holes. Will post when I can find it.

[Rikugun]

Glen, thanks for the clarification on some well documented mods.  :) As far as your V being a work in progress - most start that way and many still are! Making changes and improvements is part of the fun of motorcycling.

Regarding top speeds runs....I have what I think are realistic expectations from a Vision and the speeds you mentioned seem reasonable for a bike of this weight/HP in street trim. I'm also not surprised a fully faired example suffers a bit more from the effects of wind resistance over a naked version.

My best finish was 10th at an AMA pro 250GP race. I was one of the guys on track that made Rich Oliver look fast.

I raced only briefly raced in the mid 80's but my feeling is anything better than a DNF is a good day!

[pinholenz]

When you find them I would really appreciate your main drill size for the bolt,

And, out of curiosity, what sort of charge voltage do people get from a good stator and R/R when the bike is driving and the headlight is on?

[Rikugun]

It will vary depending on many factors including where it is measured. Mine maintains around 14.3 at the battery and I'm guessing mid 13's at the headlight? Having the original fuse block may lower this number as will poor connections including those of the left handlebar switch and key switch.

[George R. Young]

The rotor bolt as I had it drilled:
http://web.ncf.ca/ag136/bolt.jpg

[pinholenz]

Are you both using a Mikuni or a Keihin 0.7 carb jet with a slotted head for this mod ? With all the different conventions for numbering jets etc, I am confused as to what I should be ordering.

From the jpg pic it looks a bit like a Keihin 99101-124 slow speed air jet?
http://www.pjmotorsports.com/keihin-jets.html

I think I will go for style of mod that glenc44 has tried with the cross drilled head.......

[glenc44]

I used George,s drawing as a starting point and added the jet for easy changes. This also allows for plugging the whole thing if I desired. The jet is from a box of spare jets my friend has. Don't know if Mikuni or Kehien. I would go down to the nearest motorcyle or scooter store and ask to see their shop assortment. Pick something that has a head no larger in dia then the threads, and a hole around .7 mm. I don't think slightly larger  like .8 would make much difference. Then drill the proper holes for threads and counter bore, tap and install. Be creative. Thanks George for the inspiration.

[cvincer]

With old OEM  stator  &  R/R.

At idle             14.5v                with low beam on      14.7v
"  2000rpm     14.4v                     "           "               14.6v
"  2500rpm     14.45v                   "           "                14.5v

After a ride with ambient air them of  84F

R/R  temp                        149F

Stator Cover temp          229F       (black tape stuck on cover for true reading otherwise heat gun read 195)

Front Cyl Head temp       200F       (Heat gun pointed at hex nut adjacent to spark plug)

Rear    "     "       "            200F             "                 "                          "                    "

[pinholenz]

Thanks for the data, Excellent  benchmarks.