Hi Laurens,Interesting post and although i am not an engineer as such, now it all makes sense. The BMW unit has a fully supported pinion gear, and the Quaife unit does not. But why would swap the oil in the Quaife unit at regular intervals? After all, when was the last time you changed the oil in a car or a bike unit?
With the amount of 3 wheelers on the road at the moment, and that number growing would it be worth making an exploratory inquiry to BMW. After all they make the engine for the +8 and above!
Depends what you mean by fully supported. The BMW bevel box pinion appears to be supported by a single forward bearing and a further plain bearing in the main housing supporting the extended pinion shaft, which gives support either side of the pinion itself. For comparison below is the exploded view of big V twin Guzzi bevel drive which doesn't have an extended pinion shaft.
Here a pair of taper roller bearings (14) spaced apart within the removable pinion housing, support the pinion shaft. From what I can see the Quaife bevel box employs similar pinion support to that of the proven Guzzi design, so I don't think you can lay the blame there.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
