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[PWM]

Seems plausible oil can seep by the locknut threads and what appears to be a key-way on the motor spindle...just in front of splines...if this area can be kept clean, apply RTV sealant to the base threads when you assemble it...this assumes there's ample oil splash drenching the spindle face...does not look like an o-ring issue.

[smithy]

Seems plausible oil can seep by the locknut threads and what appears to be a key-way on the motor spindle...just in front of splines...if this area can be kept clean, apply RTV sealant to the base threads when you assemble it...this assumes there's ample oil splash drenching the spindle face...does not look like an o-ring issue.

The rotor shaft is solid ....and the keyway only goes a few mm on the shaft. I'm suspecting the oil may be going under the bearing inner race and the seal runner and exiting on the inside of the seal runner...but I'm not sure...if the seal itself isn't leaking, it has to be getting in somehow.

The pic below is of the rotor shaft and stator of a "spare" motor which had the same issue as mine. I have this "spare" motor at home.

Smithy.

[electrictwowheeler]

Is the surface on the motor shaft that the seal actually runs on part of the shaft or a separate part. I think you are calling it the seal runner. Is that something that is pressed or glued on to the shaft. You would think that would be machined onto the shaft itself but if it is a separate part it would have to be sealed to the shaft somehow. Maybe it is leaking there as you suspect.

[smithy]

Is the surface on the motor shaft that the seal actually runs on part of the shaft or a separate part. I think you are calling it the seal runner. Is that something that is pressed or glued on to the shaft. You would think that would be machined onto the shaft itself but if it is a separate part it would have to be sealed to the shaft somehow. Maybe it is leaking there as you suspect.

Pretty sure the bearing inner race is pressed onto the shaft. I'll have to have a good look at the rotor shaft to see if the seal runner is as you say, part of the rotor shaft....if it is, and the seal itself isn't leaking....I don't know where the oil is going through..?? I guess the seal is the only place oil can get in.

Smithy.

[Demoni]

I wish I had a ton of information to share regarding this issue but my knowledge is unfortunately limited. 

My understanding is there was a small batch of Experia motors with "inner rotor seals" that did not conform to manufacture specifications. This can cause a path for oil to leak out of the chamber where the reduction gears are located.
Most motors built using these seals leaked a very small amount of oil which although not ideal does not cause major issues. However in some cases if a large amount of fluid leaks out this can cause a lack of lubrication to the reduction gears and bearings resulting in premature wear to the contact surfaces.

The fix was to replace the seal and inspect the gear teeth for excessive wear, gears were replaced if wear was found. Wear / damage was rare and only seen on bikes that ran for extended periods when low on oil.

I do not have access to spare parts but if the faces of the gear teeth look good and the bearing races are clean my suggestion would be to install a new seal. After you refill the oil run the motor for 10km and check the level. If it does not change or only goes down by a small amount run the motor for another 100km and recheck the oil level.

[smithy]

I wish I had a ton of information to share regarding this issue but my knowledge is unfortunately limited. 

My understanding is there was a small batch of Experia motors with "inner rotor seals" that did not conform to manufacture specifications. This can cause a path for oil to leak out of the chamber where the reduction gears are located.
Most motors built using these seals leaked a very small amount of oil which although not ideal does not cause major issues. However in some cases if a large amount of fluid leaks out this can cause a lack of lubrication to the reduction gears and bearings resulting in premature wear to the contact surfaces.

The fix was to replace the seal and inspect the gear teeth for excessive wear, gears were replaced if wear was found. Wear / damage was rare and only seen on bikes that ran for extended periods when low on oil.

I do not have access to spare parts but if the faces of the gear teeth look good and the bearing races are clean my suggestion would be to install a new seal. After you refill the oil run the motor for 10km and check the level. If it does not change or only goes down by a small amount run the motor for another 100km and recheck the oil level.

Thank you so much for the reply...your understanding is the same as mine...I did indeed change the seal, unfortunatly not with a genuine one as they are just not available here in Australia.

My gears are in good condition with no excessive noise...I also have the spare motor gears to use if necessary...but at this stage I just refitted the original gears....bearings are also in good condition.

I have put ~600km on the bike since I fitted the new seal...it is "much better", very little oil is leaking though compared to before I changed the seal. I wasn't able to get the OEM seal and have replaced it with a normal automotive seal of the same size. Hopefully it will be ok.

Time will tell.

Smithy.

[DonTom]

Hi All,

There was a service bulletin released in July of '23 which noted specific VIN#'s early on in the Experia production run, Service Bulletin # 22-SI-2723, dated July 4th 2023...my Experia was on that VIN list.

I am glad you posted this! I have not checked my gear oil window for a very long time. I only had 15 CC in there when I recently drained it into a measuring cup after I noticed I saw no oil in the view window.

I didn't have the exact stuff they call for at that house when I checked it, so after I took out the 15cc of old "transmission oil", I put in 50 CC of Valvoline 80W90 gear oil. Since then, I put on around 500 miles / 800 km and I have not lost a drop, but from now on, I will keep a very close eye on it.

I have bike number 00018, so it is on the list for having the problem.

If I didn't see your post, I have no idea when I would have checked it. It would probably have been too late and then there would be some damage. I think I added the gear oil in time before any damage was done.

-Don-  Reno, NV