Riveted sprung clutch sprocket

[HxPaul]

Is it safe to use such a clutch sprocket on a 200cc motor with a Casa 210 top end.The engine is the original 210 ( the same as a Casa 185,but with a bigger piston)The reason I ask is that the clutch sprocket and spider are original Innocenti and run with the bearings and not a bush,they have no wear and assembled the clutch sprocket has no up and down movement or "rock".I would be gratefull for any info.

Paul

[AlG]

I have never fitted one, so never actually broken one, but I do have several in the 'might sometime be useful box'with loose rivets and broken springs. I believe the received wisdom is not to use them.

AlG

[Digger]

The general advice is not to use the cush-drive type in anything other than a standard engine.

[ToBoldlyGo]

I don't know. I think there comes a point when it's very nice to have original parts, but in the end you've got to be practical, and the sprung crownwheels aren't as strong. You could use them by all means, but personally speaking I think there would always be that element of doubt.

[Warkton Tornado No.1]

IMO, the two piece construction crown wheels are alright if the riveting is good, but it’s usual to split them to extend the slots these days to allow more plates/clearance. If I’m doing so, I then tap the sprocket part & use high tensile countersunk screws Loctited & torque up to reassemble.

There is a load that the better fastenings will easily cope with & I prefer screwing….

However, the standard sprung versions do not cope with much more torque, but that’s not to say you couldn’t modify them to make them work.

Something on my ‘to do’ list….

[HxPaul]

IMO, the two piece construction crown wheels are alright if the riveting is good, but it’s usual to split them to extend the slots these days to allow more plates/clearance. If I’m doing so, I then tap the sprocket part & use high tensile countersunk screws Loctited & torque up to reassemble.

There is a load that the better fastenings will easily cope with & I prefer screwing….

However, the standard sprung versions do not cope with much more torque, but that’s not to say you couldn’t modify them to make them work.

Something on my ‘to do’ list….

Thats very interesting and I think the high tensile screws is a great idea.

Thanks to everyone for there input.