Bearing Man

Sorry for late response, was just getting a few days rest over Christmas. This runout will be the Spider or chainring, nothing to do with the motor. Crankshafts will normally snap before they bend, but you only have to touch a chainring or spider and it will bend. Hope this helps.

That's great but I need to make a battery talk to a Bosch system, this seems to be to make a Bosch battery play with other systems. Great find though.

I just wanted to make range extender bottle batteries, but need BMS

Shipping dangerous goods or getting insurance to play with batteries is just a nightmare too! Wish they would sell us the BMS though... No idea how they cracked that one, very cleaver!

Such a shame they didn't make a 350W + bottle holder battery like Specialized now have

Unfortunately, longevity relies on so many things... Riding terrain, weather, washing regime, bike transporting method, etc. I have seen motors with 240 km that are destroyed, and I have seen motors with 80,000 km that are still going well. Some motors have all ball bearings and require very little maintenance, but there are a few motors out there that do need a little looking after and Yamaha is one of those motors. The Yamaha manual shows that there are several points in the motor that require greasing from time to time, but they don't tell you when? Yamaha PW and PW-SE motors have some bronze bush bearings that support the crankshaft. These bushes tend to get dry and start to wear into the crankshaft, this seems to start happening from approximately 2,400 km and eventually the wear and drag just get slowly worse.

Lot cheaper to get the motor fixed than buy a new one, that's for sure

Result!

Some have O-rings some don't. Tends to be different depending on different sprocket types. The Haibikes have one for example, but probably shouldn't. The spider nut tends to cut it into little bits and squash it beyond recognition.

I mostly see it on fat bikes, where the sprocket has been made by the manufacturer to stick out further to help the chain miss the rear tyre. These seem to put a high side load on the sprocket and some definitely become lose. But often, it's caused by fitting the wrong sprocket.

Why the sad face? This is an easy and cheap fix!

Yes, I have seen a few of those. Bosch didn't keep that idea very long did they

I see this a lot, especially if the wrong type of sprocket has been fitted with the wrong type of nut. What happens is the nut bottoms out and goes tight before it clamps the sprocket tight enough. This allows the sprocket to move and it can cut through the aluminium sprocket carrier surprisingly quickly. If Bosch don't honour the warranty (which would be understandable if the sprocket has cut through the carrier). Because you have been off the road and messed around, we will fix your motor for £25.00 at performance Line Bearings, you just pay the postage. Email me at enquiries@performancelinebearings.com if you think this option would help.

Although we are Bosch approved, no one but Bosch are approved to repair their motors. This is why we only work on motors outside of warranty or motors that people don't want to wait for warranty and are prepared to forgo it. This failure is not a service or maintenance issue, it's just one of those things that happens very, very occasionally with this motor.

The symptoms you have John are normally a cracked drive gear. It is a fairly common fault and a 5 minute fix. If Bosch throw this back at you, tell them to look at the small metal drive gear that houses the small motor drive gear clutch bearing.