Is my E8000 about to explode?

[GrumpyMTB]

Hi, looking for some opinions on this. Last couple of rides I started noticing a weird noise. The bike is a YT Decoy Shred 2020 which I've had from new since end of July 2021 (2 years, 3 months). Easiest way to explain the noise is through this video I recorded last night.

The noise only seems to occur under heavy load, like climbing a steep hill. It's noticeable in ECO, Trail and Boost, but louder in Boost. It also occurs if I switch the motor off. There doesn't seem to be any issue with the bottom bracket bearings; no play in the crank arms etc. If I rotate the BB driveshaft by hand its quiet going backwards and, well sounds like a motor going forwards. There also doesn't seem to be any drop in assistance level or slipping etc. Apart from the noise, it rides and goes as normal. Chain is new (probably only 50km) and cassette is fairly new.

 

[VWsurfbum]

Sounds like the jocky wheels (if they are the narrow wide type)

 

[GrumpyMTB]

I did have aftermarket alumnium jockey wheels on, but replaced them for the stock Shimano plastic ones and it still makes the same noise.

 

[S13]

Did you put the new narrow / wide chain correctly on the chainring?

 

[jcismo1]

Yup, that noise sounds familiar. I’d hit some rough stuff and it started making the noise. I thought for sure that the motor was toast. I discovered that the chain somehow ended up out of sync with the narrow/wide jockeys wheel on the derailleur. The chain was just a little worn I guess, because I put on a new chain and haven’t had the problem since.

 

[GrumpyMTB]

Yup, that noise sounds familiar. I’d hit some rough stuff and it started making the noise. I thought for sure that the motor was toast. I discovered that the chain somehow ended up out of sync with the narrow/wide jockeys wheel on the derailleur. The chain was just a little worn I guess, because I put on a new chain and haven’t had the problem since.

It's weird because I've recently put on a new chain. I took it to my local bike shop today to get a 2nd opinion, and before I did I put the old chain, old cassette etc back on and when I got to the shop it wouldn't make the noise... now I'm thinking the out-of-sync thing could be it. The only part of the drivetrain that's out of step in terms of age/wear is the chainring. So my next step will be new chainring, chain, cassette and jockey wheels and will see if that solves it. Thanks.