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[PWM]

Hmmm, it seems from the legacy wiring diagram (Ego/Eva 2020-21) that all 12V circuits on the Energica return to ground, suspect this is chassis ground...easy to check...and if so, then all handle bar elements e.g. head-lights too will have ground terminations at chassis.

If there was substantial fault current to effect steering head bearing then it would be coming from the lighting circuit, check where the headlights ground to maybe a loose ground termination could cause the bearing issue as described.

A bonding jumper is more indicative of switch mode noise suppression measure...not sure if that would be for radiated noise on the Zero, but Energica doesn't show such in the wiring diagrams for the early bikes anyway.

[Specter]

PWM even if that were the case, even if it is pulling 4 amps, there simply isn't enough energy for that current to really get thru the grease on the bearing, you'd immediately know it, it'd throw that light fault, the connection would not be a solid one thru the bearing that it can't penetrate the grease and the current would be bouncing all over the place that'd throw a lighting fault.

energica monitors the current going to the lights and if it's goofy it throws a fault.

any currents induced by the pwm would be switching spikes or induction in the motor shaft most likely because they ARE connected to that 'system'  any bearing issues would be back there,  motor bearings or less susceptible, the rear wheel.

ESok just because you want to keep doubling down on i don't have a clue how a system works does not automatically make you correct because a component exists that is not used in the system you are concerned with  good lord son..

why don't you try this, since you are so in love with ai,   ask ai if a bad grounding strap can cause arcing thru the head bearing on that bike, if you are going to be stuck on stupid, at least let the ai have a good laugh too.,   

Aaron

[ESokoloff]

……since you are so in love with ai, …..

Aaron

Not sure how you reached this (inaccurate) conclusion.

[ESokoloff]

Hmmm, it seems from the legacy wiring diagram (Ego/Eva 2020-21) that all 12V circuits on the Energica return to ground, suspect this is chassis ground...easy to check...and if so, then all handle bar elements e.g. head-lights too will have ground terminations at chassis.

If there was substantial fault current to effect steering head bearing then it would be coming from the lighting circuit, check where the headlights ground to maybe a loose ground termination could cause the bearing issue as described.

A bonding jumper is more indicative of switch mode noise suppression measure...not sure if that would be for radiated noise on the Zero, but Energica doesn't show such in the wiring diagrams for the early bikes anyway.

With a predictable premature operating lifespan from multiple mechanics & manufacturers as well as knowing that AC motors on VFD produce static electricity, it sure seemed plausible that a lack of bonding conductor between frame/steering head could allow EDM (Electrical Discharge Machining) to cause bearing damage.

If the Expedia indeed uses the chassis as 12v ground then my theory goes out the door.
My 2016 Zero DSR has no electrical reference to ground that I’m aware of & assumed this was due to its EV design & made another assumption that Experia was the same.

I’m curious as to how Experia handles motor static?

[Demoni]

ESokoloff and Specter please dial it back a few notches the quips and jabs are getting old. Not looking for explanations or a reply but have respect for other members of the forum. First and last warning. Now with that out of the way...

If the Expedia indeed uses the chassis as 12v ground then my theory goes out the door.
My 2016 Zero DSR has no electrical reference to ground that I’m aware of & assumed this was due to its EV design & made another assumption that Experia was the same.

I confirm Energica uses the frame as the 12V ground reference. The HV+,- are floated but the 12V system is wired just like any ICE motorcycle.
There is continuity between the frame and triple trees resulting in no voltage differential.

The Energica motor is tested and confirms to EU regulations for EMF radiation. Do not have specifics on how it manages all of it's isolation. I can say that all 3 phase wires have a braided wire shielding layer that is grounded at the motor and inverter sides, this also provides HV leak detection.

[ESokoloff]

ESokoloff and Specter please dial it back a few notches the quips and jabs are getting old. Not looking for explanations or a reply but have respect for other members of the forum. First and last warning. Now with that out of the way...

If the Expedia indeed uses the chassis as 12v ground then my theory goes out the door.
My 2016 Zero DSR has no electrical reference to ground that I’m aware of & assumed this was due to its EV design & made another assumption that Experia was the same.

I confirm Energica uses the frame as the 12V ground reference. The HV+,- are floated but the 12V system is wired just like any ICE motorcycle.
There is continuity between the frame and triple trees resulting in no voltage differential.

The Energica motor is tested and confirms to EU regulations for EMF radiation. Do not have specifics on how it manages all of it's isolation. I can say that all 3 phase wires have a braided wire shielding layer that is grounded at the motor and inverter sides, this also provides HV leak detection.

Who started the attacks?

Just so there is common understanding with what I propose is at play & in need of confirmation or proof of non existence is as follows.

3 ph AC motors controlled via a VFD produce static electricity that will cause EDM bearing damage if not mitigated.
The fact that this bike has had 3 bearing failures via 3 mechanics using 3 different manufacturers to me rules out materials & installation faults.
If the bearing alignment was at fault it seems like it would managed immediately.
The failure rate is a predictive time frame so I felt that EDM was THE cause.
I shouldn’t have been so positive of it but merely suggest that it be ruled out which I did by suggesting confirming that the head stock is bonded to the frame thus eliminating any chance of EDM through the bearings.
You say that there is continuity between the frame/head stock.
Is this via a common ground or bond conductor (as apposed to via the roller bearings)? 

I got/get the sense that Spector doesn’t understand what I was trying to convey
& blindly shot it down via the first volley.

Also I miss spoke when I wrote that my Zero has no electrical reference to the frame.
The onboard charger/level one power source (115vac) & frame are referenced to mains earth ground.

Motoproponent & others experiencing this issue keep us up to date on this “who done-it” mystery.

[T.S. Zarathustra]

Before coming to the conclusion that some sort of electric leakage is causing damage to the head bearings (not impossible, but not plausible either) why not ask if the bearing seat is machined correctly? There might be minor misalignment that accelerates bearing failure. In my experience one of the most common failure of properly lubricated and correctly mounted bearings. It doesn't take much. Maybe if we see a photo of failed bearings it would be easier to make educated guess as to the cause of failure. Electrical discharge will eat a hole into the surface.
Another possibility is under-specced bearings. That are not strong enough to withstand the forces in small number of cases.
Another possibility is water getting into the bearings. Either through damaged seal or some other way. I remember replacing bearings in a motor three times in five years, before figuring out that the people working with the equipment used pressure washer to clean after each shift. Then we made a new cover and as far as I know the motor has now been running for 30 years.
Another possibility is bad batch of bearings.

[Richard230]

Years ago I owned a 20K-mile 1992 Honda CB750 that after 10 years developed stiff turning and notchy-feeling steering bearings. So I had them replaced and asked for the (ball-type) bearings and races to be returned to me. It turned out that the bearings were in perfect condition. The problem was that the grease had dried out and had turned hard and stiff. Once I cleaned out the old grease, I was amazed that the bearings and their races looked and felt like new.

[Motoproponent]

yeah, it's definitely not old grease.

I will look and see if I still have the old bearing races. I don't think I do, but I will say that the outer race has a series of vertical lines visible. They were spaced to coincide with the contact of the rollers. If you cleaned the race you can just barely feel them with your fingernail. And only three or four would be detectible with the fingernail, but all the contact points were visible to the eye. long linear, regularly spaced vertical marks.

I don't think that is consistent with EDM damage.

The front of the lower triple has some of the black coating rubbed off. How could I check for an improperly machined seat or something else that would misalign the steering stem?

[Specter]

that sounds like a lubrication issue, or pehaps they were over tightened.  damage can accumulate over time as well, from the repetitive back and forth.  misalignment maybe from the overtighten crunched one side down a bit or something?

yes pictures would be great, so we can see exactly what the damage looks like.

normally when those bearings fail, it's damage, from over tightening, they took a shock, maybe in a crash, or smashed a pothole real hard, notched it and it want from there.  or lubrication issues.  grease dries out, was not put in properly, or moisture gets in, starts to rust stuff or compromises the quality of the lube and it starts going from there.

edm damage will look kind of like spiderwebs, and will leave little craters in the metal, because what's happening is the arc is vaporizing the metal at point of inception so if you magnify it, it looks like a little meteor crater.

i wonder if those lines coincide with limits of travel?  curious.

aaron

[ESokoloff]

……
the outer race has a series of vertical lines visible. They were spaced to coincide with the contact of the rollers. If you cleaned the race you can just barely feel them with your fingernail. And only three or four would be detectible with the fingernail, but all the contact points were visible to the eye. long linear, regularly spaced vertical marks.

I don't think that is consistent with EDM damage.
……….

https://www.google.com/search?q=false+brinelling+vs+fluting&ie=UTF-8&oe=UTF-8&hl=en-us&client=safari

From this side of the keyboard it sounds like false binelling caused by being continuously subjected to constant vibration @ standstill (which is most of the operating time) or fluting caused by electrical current.

Are the roads you ride excessively rough?
Per chance do you feel any vibrations in the steering on a smooth section of road?
If you take your hands off the bars will the steering go into tankslapper mode?

As previously stated I had to change the bearings on my Zero @ 45k miles & I packed the new ones with AeroShell 14
https://www.shell.com/business-customers/aviation/aeroshell/aeroshell-greases/aeroshell-grease-14.html
as it has properties designed for bearings that don’t move far (rotate) but move constantly.
Now at 95k miles & no issues.

Suggest you contact bearing suppliers to discuss your issue & see what they have to say about bearing wear cause & cure (including lubrication recommendations).

10,000 miles is what, 225 operating hours? (based on 40mph avg).
That low of hours is nothing to a bearing in a NORMAL application.

[Motoproponent]

Are the roads you ride excessively rough?

Lol, San Francisco Bay Area roads are basically third world. Plus when I go out for a fun ride I'm all about the backroads we call "goaty". Like a goat trail with deteriorated surface, usually no pavement markers and a lot of tree roots and potholes.

So, yes...90% of the roads I ride are excessively rough.

Suggest you contact bearing suppliers to discuss your issue & see what they have to say about bearing wear cause & cure (including lubrication recommendations).

10,000 miles is what, 225 operating hours? (based on 40mph avg).
That low of hours is nothing to a bearing in a NORMAL application.

My bearing suppliers are teenagers with a parts look up computer that cant sell me an 1157 light bulb if I don't give them the year, make, and model of a car that uses them (because they don't sell motorcycle parts so telling them its for a 1979 Kawasaki shuts them down like a switch). If i don't give them the part number they don't know what the bearing is much less an alternative application that would meet my use case better.

[ESokoloff]

Are the roads you ride excessively rough?

Lol, San Francisco Bay Area roads are basically third world. Plus when I go out for a fun ride I'm all about the backroads we call "goaty". Like a goat trail with deteriorated surface, usually no pavement markers and a lot of tree roots and potholes.

So, yes...90% of the roads I ride are excessively rough.

Suggest you contact bearing suppliers to discuss your issue & see what they have to say about bearing wear cause & cure (including lubrication recommendations).

10,000 miles is what, 225 operating hours? (based on 40mph avg).
That low of hours is nothing to a bearing in a NORMAL application.

My bearing suppliers are teenagers with a parts look up computer that cant sell me an 1157 light bulb if I don't give them the year, make, and model of a car that uses them (because they don't sell motorcycle parts so telling them its for a 1979 Kawasaki shuts them down like a switch). If i don't give them the part number they don't know what the bearing is much less an alternative application that would meet my use case better.

Do you still have all your fillings?

Pondering this a bit more I’m thinking that the new roller bearings need an initial tension adjustment followed by a re-adjustment after they “seat”.

Any chance you know the position of the races in relation to front/back of the bike?
You wrote that the race(s) had marks consistent to the bearing count & that the indent depth wasn’t consistent.
Theorizing that with loose bearings the excess play would allow greater contact force (banging) on the back of the bottom bearing & the front side of the top bearing as the bottom bearing would act as a fulcrum to the shock tubes acting as levers when encountering rough road surfaces.

Obviously this bearing wear  (TRUE Brinelling [not False Brinelling/miss spoke]) is not exclusive to Energica so ask for advice via other motorcycle resources.

https://www.fjrforum.com/threads/how-often-do-you-re-torque-the-steering-head-bearings-if-they-seem-ok.176846/

SKF Suport
https://www.skf.com/us/support/contact/technical-support

[Specter]

mp, do you have any motor rewind shops around, or alternator repair places, or even flat out bearing suppliers like barry bearing.

they should be able to cross you with other manu's or even find stuff given the specs you give, what you need it for etc etc.

i remember in the navy a few times, we had issues, and the supply system was shit, didn't have things and with a bit of creativity and knowing who / where and most importantly what to ask, were able to figure out that, the bearing i needed for my jacking gear motor was the same as on a pump that is used in nuke stuff in specific apps, and also used by skippy in one of their peanut butter pumps... of all places.  so once you know of different places this may be found, a bit more detectiving, can get you to a part you need hopefully.  just remember if changing orientation, axial vs radial as an example, that you may need a bearing that supports a thrust component too.

aaron

[Motoproponent]

My plan for now is to wait and see if the suspension adjustment has any effect on the rate of wear.

I'll let other Experia owners catch up to me in mileage and see if it's and Experia issue or an Experia VIN#0094 issue.

I have no trouble getting SKF bearings at a good price, and now that I have all the tools its a 1 day DIY job to replace the head bearings. Each replacement is more data and eventually we (collectively me, the forum, and @Demoni with Energica and Co in South San Francisco) will figure it out.