stator running hot

[The Prophet of Doom]

Thanks CVincer
in proper measurements...

After a ride with ambient air temp of  29C

R/R  temp                        65C

Stator Cover temp          109C      (black tape stuck on cover for true reading otherwise heat gun read 91C)

Front Cyl Head temp       93C       (Heat gun pointed at hex nut adjacent to spark plug)

Rear    "     "       "            93C             "                 "                          "                    "

[pinholenz]

That's better, now those are numbers that I understand!

Had a productive hour today at the local bike wrecker scouring through a mountain of brass emulsion tubes and jets to find a jet that would do the bolt mod. Got a couple that look like #70 that should be perfect and 3x #80's unbranded with  heads  wider than the thread diameter. They would do at a pinch.

[Jirik]

I have two questions, probably to glenc44:

1/ Is jet screwed to bolt or is it only interference fit?
2/ Is bolt head drilled from two sides or just one hole?

I borrowed George's picture.

[Rikugun]

This is my understanding of glens work so if I'm mistaken I'm sure he'll clarify.

1/ Is jet screwed to bolt or is it only interference fit?   screwed into cut threads
2/ Is bolt head drilled from two sides or just one hole? one

Additionally, the jet resides below the cross drilled hole shown in red in george's borrowed diagram. The end of the top hole is sealed to force oil to travel through the single cross drilled opening.  ;)

[Jirik]

OK, thank you.

[pinholenz]

I have modded Georges diagram again. Thanks George. Hope this helps

I guess it wont make too much difference if you drilled right across the bolt or on just one side, but straight across would keep things balanced.

[jasonm.]

2 things. 1st...dielectric grease...should not be packed into connectors. Dielectric means "insulator". Thus impeding electron flow. This grease was designed to keep water out of automotive distributor caps and spark plug wires and NOT conduct the high spark plug voltage. Thus, use it sparingly.2nd- The rotor/flywheel bolt drilling does help. Yamaha did this on the Ventures  after the 1st year '83 models fried stators in less than 20k miles.  There after all Venture 84 on has the drilled bolt and washer design. The washer is oddly shaped to ..I guess help spread the pressurized oil. Note: the washer does not move.  Does not move but distributes the oil on the stator.That's why I call it special.  I honestly do not know the spec/size of the hole which sprays out the end. Unlike the diagrams I see pictured here, the yamaha design sprays stright out the end. Not radially.No cross drilling. I have 2 Ventures and still cannot figure out that TINY hole's bore size. The oil cooling works...but it does cost some loss of oil pressure. Meaning during summer temps you must run a 15w50, 20w40 or 20w50 oil. My Venture runs 20w50 Mobil 1 90% of the year. GLENN, Lastly, I do not understand  exactly where you drilled the 1/8" holes. They just for drainage of oil?

[cvincer]

jasonm  ........  will the Venture rotor/flywheel bolt fit the Vision?  If yes, would be easier to buy than drill.

[Re-Vision]

Curious as to why you are concerned about packing a connector with dielectric grease, looks like it would just offer that much more protection from corrosion and moisture. Current will flow in metal to metal contact and shouldn't decrease until resistance increases or moisture shorts it out.     BDC

[Night Vision]

jasonm  ........  will the Venture rotor/flywheel bolt fit the Vision?  If yes, would be easier to buy than drill.

The Venture rotor bolt upgrade included several parts other than the bolt... plate covers to confine the oil, and a "slinger" to distribute it...

http://www.venturers.org/Tech_Library/?action=article&cat_id=001007&id=413

[Rikugun]

This from the interwebs which everyone knows is infallible.   ;D

"Dielectric grease is a silicone-based lubricant that does not conduct electricity. This is a very useful property to both waterproof and prevent corrosion on electrical connections. Because the grease does not conduct electricity, it will not interfere or scavenge power from the electrical current going through the connection. This makes it an ideal coating and protectant for any electrical connection from CPUs to automotive batteries and everything in between." 

The same source warns:  "Although dielectric grease is advantageous if applied correctly, it can also be disadvantageous if applied incorrectly and may prevent a conductor from working at all. Dielectric grease is non-conductive, so if the user does not properly clean the conductor's contact points after applying dielectric grease, current will not pass through them. Dielectric grease also has the potential to melt silicone rubber after several years so they should not be used with conductors that are encased in this type of material."

Like anything else following directions yields the best results. My only gripe is it seems to dry up in connectors fairly quickly.

[jasonm.]

Slinger ?  actually that wire piece stays in the bolt and supposedly keeps it clean. It cannot be seen from the outside

[injuhneer]

I know this thread has been idle for a while.

In the case of the Venture kit linked earlier in the thread the metal plates are dams. They would cause some oil to be retained. I assume that pooling a bit of oil was the intent.

Being new to the Vision(s) I have been reading the threads. I haven't read all of them but had an idea similar to glenc44. The bolt drilling is a good concept but to transfer heat from the stator it needs to be continuously bathed all around. The bolt with what amounts to angled nozzles is good if the oil reaches the stator.

I have not disassembled my engine yet so I don't have a reference for the relationship or position of the components inside the cover but am certain that another solution would be to spray oil on the longitudinal center line of the stator. There is a lot of turbulence inside the cases and given the shape of the case interior (I do have a loose spare) an approach like the Venture kit would be an improvement.

I am thinking about getting the oil to the center of the stator and distributed as close as possible so it is not blown around but flows where desired. To do this would require a slightly different approach. The bolt would be drilled banjo style with a passage in the center and two small passages below the bolt head. The washer would be replaced with a cup that acts as the washer and as a slinger. The axial height of the cup would be equal to the distance from the end of the crank to the longitudinal centerline of the stator. This would sling the oil onto the stator all around.

Something like this:



I considered the idea of simply drilling the hub of the rotor to do this but a simple bolt-on piece seems like a better idea.

To see if this behaves as I am hoping I am also making a plug for the case that will let me put and endoscope in the case while the engine is running to observe the oil dispersion.

[Walt_M.]

Hi Mike, the stator heat solution seems to be solved by using a series R/R, look at the thread below. SH775 R/R. The series R/R limits the output current from the stator,  less current equals less heat. This also leaves the oil system intact.

[injuhneer]

Copy that.

I'll probably do both.

[jefferson]

Your bearings need that oil a lot more than the stator does and if one of them spins it is a lot worse than putting a new stator in. I would do the sh775 r/r which will run cooler and even the engine oil ends up cooler with the stator not putting out all that heat.

[injuhneer]

Have any values on the pump output volume been taken?

[Walt_M.]

A known history of rod bearing failures leads us to believe the oil pump output is just adequate. There are some engines out there that have been modified but I don't know if the oil pumps have been modified for more longevity.

[injuhneer]

Thanks sir.

I guess I'll open the cases on my spare engine to have a look.

Do you know if these failure are pressure/volume related? Failure of the nylon drive gear related?

I am building a 164cc stroker engine for a Honda ST-90 and have fitted a pump for the ATC185. More volume and other good things.

Maybe I'll take a look at an oil pump upgrade. Maybe larger pump, different gearing. Maybe even relocation (that is a comparatively large and long oil pick-up). The gen 1 VMax engines have their pump in the sump with a short run to the pick-up. Is there a check valve in the pick-up of the Vision pump? Even the Yamaha service manual has little info on the pump.

[injuhneer]

Your bearings need that oil a lot more than the stator does and if one of them spins it is a lot worse than putting a new stator in. I would do the sh775 r/r which will run cooler and even the engine oil ends up cooler with the stator not putting out all that heat.

There are probably performance gains, albeit small, due to the lowered parasitic load on the crankshaft.   :D