There's a guide to posting photos on the welcome forum.
You'll soon get used to the clonks, whistles, chirps etc.
Good spot on the Quaife servicing service - it'll be interesting to ask if they would service a M3W Bevel box as up to now they have referred enquires back to MMC.
When searching for a possible explanation for our screaming bevel boxes I wanted to see how BMW makes their bevel boxes on their motorbikes (which don’t scream) In a German motorcycle magazine I found a picture of a rear wheel drive of the BMW 1200 GS. And as you can see on the pictures they looks similar except the support of the pinion wheel !!
The picture on the BMW unit shows that the pinion shaft is supported on both sides. But ………. (so far as I can see) in the Qauife bevel box there is NO support on the end of the pinion shaft !! For the pinion shaft it has only one bearing in the main housing and probably one more bearing in the screwed on removable bearing housing which get attached to main housing. (so far as I can see on the picture) So both bearings of the incoming shaft are on the same side.
When driving, the pinion wheel is trying all the time to push itself out of the crown wheel due to the force on it. Because there is only support on one side of the incoming shaft, it will create (depending on the load) a huge force on this bearings. The bearing near the crown wheel will get a force away from the crown wheel. The force on the bearing in the removable housing will be to the opposite direction ! Due to this force, the shaft try to move the removable bearing housing (which is bolted on the main housing) to one side. And because it’s just bolted on there will be always some movement possible.
When shimming the whole unit for optimum play between the teeth there is no force on this removable bearing housing. When driving and applying force on this removable bearing housing it will be forced in one direction. But that direction will create more play between the teeth of the pinion and the crown wheel Which also results in the fact that optimum shimming will be impossible, because when shimming this force on this removable housing is not there. So far as I know the amount of noise is very critical to the amount of play between the teeth. So everyone can understand that if we get more play we’re getting noise. Explains also why the noise is gone when taking your feet of the throttle because the force is gone which pushed the pinion wheel out of the crown wheel so don’t create the biggest play possible anymore.
This also could explain the leaking which some boxes have on the incoming seal because the shaft will be pushed all the time to one direction/side in the seal (also because of the length leverage bearing and seal) The difference in noise level when hot can also be created by more play between the wheels due to the expansion of the housing.
Is my simple view correct ? I don’t know but it looks to me a explanation for the noise. What can we do about it ? The best way would be a better layout (like BMW) but that means there need to be complete new bevelbox developed. Perhaps a better fixation for the removable bearing housing to the main housing will also do the job so the two housings will more act as one piece.
Who can we blame for this ? Quiafe ? They say: We made it how MMC told us to make it. Can we blame MMC ? They say: It’s constructed by Quiafe and they are the specialist in this field. We only can hope that a company ( Garage 56 ? ) develops a better constructed piece of machinery (like the upgrade of the compensator to the Centa unit)
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!
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
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!
The manual of BMW says that the oil for this unit doesn't need to be changed. With normal use it can used lifetime with no KM restrictions
