Final Drive Oil

[Pukmeister]

Random thought - there is a 'gearbox' (as Yamaha describe it) where the drive comes across the bike from the CVT on the RHS to the chain drive on the LHS, with a couple of gears. I only know this as its where a bearing failed on my mk6! This doesn't seem to require any maintenance, which seems rather odd!

That is just a set of reduction gears from the crank/primary drive output before it turns the clutch basket to drive the chain/output. Its all lubed internally via engine oil so doesn't need any maintenance.

To 'fess up, I did overlook a chain lube replacement at one service, I then drained/replaced at 12,000. It was still spotless and as the oil is good for many tens of thousands of miles in an extreme pressure gearbox I can see no harm being done.

[Data]

Possibly gets a feed from the engine oil Grumpy. It's unlikely to be a sealed bearing. But then I'm not very familiar with the Tmax motors, never had one apart.

[Pukmeister]

I recently did a clutch change on my Mk3 and when you pull the clutch basket out as a complete assembly, the drive gears you mention are sat behind them and drive the clutch basket. As they are internal to the crank cases they are lubricated/cooled by engine oil, as is the wet clutch pack.

[MrGrumpy]

I recently did a clutch change on my Mk3 and when you pull the clutch basket out as a complete assembly, the drive gears you mention are sat behind them and drive the clutch basket. As they are internal to the crank cases they are lubricated/cooled by engine oil, as is the wet clutch pack.

Interesting. I assumed they were external...though as I said I wasn't aware of their existence till a bearing failed. The repair must have been an even bigger job than I thought. Fortunately the aforementioned bearing failure was 'almost unprecedented' according Yamaha.

[Data]

It's essentially the gearbox output shaft bearing. I'm guessing your bearing had a problem in that it wasn't hardened correctly or the oil supply may have been compromised. Sometimes swarf from the motor can partially obstruct the oil way. The dealer would have been looking for that issue too.