Shimano motor gear problem

[Cristian]

Hi guys I thought my motor had a broken plastic gear because the pedals were spinning without any noise. Instead the gears seem fine while there are cylinders attached to the magnet of the pedal shaft.
can someone help me fix it?

 

[steve_sordy]

Hi guys I thought my motor had a broken plastic gear because the pedals were spinning without any noise. Instead the gears seem fine while there are cylinders attached to the magnet of the pedal shaft.
can someone help me fix it?

View attachment 160446

I have never seen inside a Shimano motor, but those "cylinders" look like the rollers from a roller bearing to me.

 

[Rod B.]

Hi guys I thought my motor had a broken plastic gear because the pedals were spinning without any noise. Instead the gears seem fine while there are cylinders attached to the magnet of the pedal shaft.
can someone help me fix it?

View attachment 160446View attachment 160608

Cristian,

Like Steve Sordy, I've not had the opportunity to open up a Shimano motor and see it's internals. So, I am guessing that what I am seeing in the pictures is a damaged sprag clutch. The large cylindrical rollers are consistent with the rollers used in sprag clutch designs. The sprag clutch allows the motor's spindal shaft to rotate freely counter-clockwise and engage the motor when the shaft is rotated clockwise.

Typically when a sprag clutch begins to go out, you'll hear grinding/rumbling noises when you rotate the motor's spindle shaft. Once a sprag clutch wears out, it cannot be repaired and must be replaced.

Unfortunately, Shimano refuses to provide riders with self servicing parts, details or diagrams on motor internals. Were it a Bosch motor you could do the repair yourself or take the motor to a motor repair service center. Unfortunately, Shimano keeps a tight lockdown on it's motors and Shimano does not offer a motor rebuild kit or even want you to self service the motor.

If your motor is out of warranty, Shimano wants you to purchase a newly rebuilt motor using your local bike shop for the transaction. You'll need to exchange your broken motor for the new motor. If your motor is covered under warranty (Two years), then don't mention you took the motor apart. Put it back together and try to get a warranty replacement.

Good luck,
Rod

 

[steve_sordy]

My first thought was a sprag clutch, but I ruled that out because the "sprags" were round. I was apprenticed to a company that made and sold sprag clutches and several years later I once specified them in an engineering solution. There was no way that the sprags could be mistaken for a cylinder. Their cross-section looked like a cartoon version of a dog's bone and they used a spring to keep them in the correct orientation. As long as the designated race (inner or outer) was going faster than the other all was well. But as soon as the relative motion tried to reverse, instant lock-up!
But I am happy to accept that after more than 50 years, there will be more than one shape for a sprag, as long as it's not round. A slightly "not round" cylinder could work as a sprag in a different clutch design.

 

[Rod B.]

My first thought was a sprag clutch, but I ruled that out because the "sprags" were round. I was apprenticed to a company that made and sold sprag clutches and several years later I once specified them in an engineering solution. There was no way that the sprags could be mistaken for a cylinder. Their cross-section looked like a cartoon version of a dog's bone and they used a spring to keep them in the correct orientation. As long as the designated race (inner or outer) was going faster than the other all was well. But as soon as the relative motion tried to reverse, instant lock-up!
But I am happy to accept that after more than 50 years, there will be more than one shape for a sprag, as long as it's not round. A slightly "not round" cylinder could work as a sprag in a different clutch design.

Steve, you are absolutely correct, my bad, It would have been better if I said it was some form of a "Roller" clutch design and not specifically a sprag clutch.

I've searched online and tried to find somebody or motor repair center who has taken an EP8 motor apart and posted photographs of the clutch assembly. It's a virtual desert, I found nothing. Shimano did post a generalized exploded diagram of an EP8 motor, but the diagram does not go into any detail on the clutch assembly or how it operates. You can see it here in the screen capture. The clutch assembly slides over/encompasses the motor's torque sensor.

TQ motors use a roller clutch design. The TQ clutch looks some what similar to the rollers and castle type race seen in Cristian’s photographs.

I realize that none of this matters or helps Cristian. Shimano doesn't provide parts or diagrams to assist in motor repair.

 

[Cristian]

anyway guys if anyone has that piece I would be interested in buying it

 

[cream]

That roller clutch is part of the torque sensor assembly. I have that roller clutch intact but the torque sensing element is bad. You’ll have to move the rolers/springs to your piece, assuming the roller seats are fine.

 

[murak]

I think this is what it should look like. Maybe you can put it together yourself, I don't know. Worth a try if it's out of warranty.

Picture is from a repair shop, don't remember it's name.

 

[RustyIron]

But I am happy to accept that after more than 50 years, there will be more than one shape for a sprag, as long as it's not round. A slightly "not round" cylinder could work as a sprag in a different clutch design.

Well tickle my crumpet and call me Lord Biscuit!
I was working on "sprag clutches" back when many here were still sucking on mama's teat. Now you tell me those aren't sprag clutches at all! What I thought was a sprag clutch was really just a cylindrical roller in a tapered hub pocket.

Now I don't know what to do next time I'm having a conversation. Should I use the term "one-way freewheel clutch," or should I just say "sprag clutch?" I suspect I'll do the latter, just as I ask for a Kleenex rather than a "wood-based soft textured snot rag."

Thanks for the education.

 

[Rod B.]

anyway guys if anyone has that piece I would be interested in buying it

Cristian,

Occasionally you'll find new and used eBike parts listed for sale on Pinkbike in the Buy/Sell section. You can search Europe, regional and worldwide. Your original post doesn't mention which Shimano motor you have, but you can find both an EP8 and an EP801 being offered for sale. By the time you factor in shipping, either motor may be too costly. Just wanted to give you a head's up that they are available in case you can't fix yours.

Mountain Bike Marketplace | Used Mountain Bikes and Parts | Pinkbike

Explore North America's largest marketplace for used mountain bikes and parts.

www.pinkbike.com

There is a used EP8 motor being offered for sale out of Britain.

There is also an EP801 motor being offered for sale in the states.

 

[Rod B.]

andrzejwodejszo

www.emtbforums.com

francisscoasismm,

I see from your title that you possibly located in Badajoz Spain. I've used Google Translator to answer your question in Spanish. I hope it translates my response correctly....

Por el título, veo que posiblemente te encuentres en Badajoz, España. He usado Google Translator para responder a tu pregunta en español. Espero que traduzca mi respuesta correctamente.

Shimano no ofrece información sobre cómo reparar motores Shimano por cuenta propia. Por ello, no hay mucha información online sobre cómo repararlos.

Shimano tampoco vende repuestos para motores averiados.

Supongo, pero si las bielas giran libremente y el motor no engrana, es probable que se haya estropeado un cambio, un embrague o un sensor de par del motor.

Veo en tu perfil que eres de Badajoz, Portugal.

He buscado online y parece que hay una empresa en España, cerca de ti, que repara motores Shimano averiados. La empresa se llama eBikenn.

Aquí tienes la dirección web de eBikenn:

Reparación de Motores de Ebike Shimano | Ebikenn

Especialistas en la reparación de motores de Ebike SHIMANO. Ebikenn es la única empresa del mundo que fabrica sus propios embragues. REPARA TU MOTOR SHIMANO

ebikenn.com

Deberías enviar un correo electrónico a la empresa y espero que puedan ayudarte o reparar tu motor.

Espero que te sirva de ayuda,
Rod

Spanish Web Version:

Reparación de Motores de Ebike Shimano | Ebikenn

Especialistas en la reparación de motores de Ebike SHIMANO. Ebikenn es la única empresa del mundo que fabrica sus propios embragues. REPARA TU MOTOR SHIMANO

ebikenn.com

English Web Version:

Shimano Ebike Motors | Ebikenn

Now your Ebike motor can be repaired.

ebikenn.com

 

[ped]

Hi Cristian,
i ride an orbea rise m20 with EP8 motor. At km24300 i faced a similar problem as you have now.
The plasic cage holding the rollers was broken and a dislocated roller compromised the clutch body.
Due to the poor sparepartpolicy of shimano,( Rod B. already described it ) i purchased a EP8 on ebay.
This motor had an unrepairable electric fault. I guess it was error E010 and price below 80€.
I used the spagcluch and the axel from this motor to fix my EP8.
The motor runs without any problems since then. Km today 37500.
I attached some pics from the inside and broken parts, maybe it helps.
Looking at your pics, it is not visible that the plasiccage holding the rollers is broken.
To be shure, you shoud dismout the boards a little further.
Probably it is sufficient to place the rollers back into correct position, give them a grease and and give it a try.
The cranks should easily rotate backwards without any scratching or grinding noise. Rotating the cranks forward, you should feel a little more resistance, but still smooth and no scratching. No chain on the chainwheel for this test.
best regards and good luck
peter

 

[murak]

@ped Thank you for the very useful info and pics! Do you have any pictures of the clutch with new grease applied before reassembly? Did you use Shell S2 V100 2?

 

[Rod B.]

Hi Cristian,
i ride an orbea rise m20 with EP8 motor. At km24300 i faced a similar problem as you have now.
The plasic cage holding the rollers was broken and a dislocated roller compromised the clutch body.
Due to the poor sparepartpolicy of shimano,( Rod B. already described it ) i purchased a EP8 on ebay.
This motor had an unrepairable electric fault. I guess it was error E010 and price below 80€.
I used the spagcluch and the axel from this motor to fix my EP8.
The motor runs without any problems since then. Km today 37500.
I attached some pics from the inside and broken parts, maybe it helps.
Looking at your pics, it is not visible that the plasiccage holding the rollers is broken.
To be shure, you shoud dismout the boards a little further.
Probably it is sufficient to place the rollers back into correct position, give them a grease and and give it a try.
The cranks should easily rotate backwards without any scratching or grinding noise. Rotating the cranks forward, you should feel a little more resistance, but still smooth and no scratching. No chain on the chainwheel for this test.
best regards and good luck
peter

View attachment 160977 View attachment 160978 View attachment 160979 View attachment 160980 View attachment 160981

Ped,
Awesome description! Thank you for the info, great job!

 

[ped]

@Rod B.
thank you very much for your kind recognition.
@murak
Sorry, i did not take any further pics.
The grease, used for the clutch, was nothing special, just a NIGRIN standard grease.
See enclosed pic.

 

[ped]

Greetings to everybody following this thread.
Just an upate to the sprag clutch repair at km 24300.
Now i am on km 41500 and the motor still runs without any problems since then.
I am curious how long this motor will last in the end.
Even the battery is still in an good condition.
Does anybody know, if there is a thread about repair history and lifetime of ep8 machines ?
Regards to everybody.

 

[ped]

thanks for your bikedata. 100000km is an ambitious aim. Let"s see how far we get.
Good luck.

 

[ooartur]

E-ves in netherlands sells this part for 100 eur