Crankshaft shock absorber

[nortom]

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Good evening! How can it be that the shock absorber cannot snap over? The spacer behind the crankshaft sprocket is the correct width. The gear is new from AMOC. Is it the wrong crankshaft?

Greetings Thomas

[nortom]

...or shouldn't he snap?

[cfaber]

Should look like this:

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IMG_20190401_193537.jpg

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[Taid]

I could be wrong, but wouldn't expect it to be able to 'snap' over .. it's just to absorb initial hard acceleration..

[nortom]

I have never seen such a shock absorber before. My Norton doesn't have one. I thought it should be able to snap over if the torque is too high, because it has no limit in the curve. But that would not work because it would run against the washer and screw on the shaft...

Greetings Thomas

[nortom]

Another old friend repairs old Harley's. He also wrote me that the damper should not snap over. Old HD's have the same damper. Thank you guys!

[cfaber]

Yeah it shouldn't, there's not enough clearance with the sprint compressed. Probably if it did you'd break the spring as well.

[nortom]

My father's old NSU probably also has this shock absorber. I just never saw it ...

Greetings Thomas

[SPRIDDLER]

What is the history of the bike? Was it unassembled when you bought it?
There's something that doesn't look right in your assembly but I can't work out what it is.
Your 1952 engine would have had a dynamo and a spring and cam shock absorber (as in Colin Faber's photos) but from your photo I can't see a dynamo drive sprocket behind the primary drive sprocket. The primary drive sprocket in your photo looks new to me.
Later engines had an alternator so didn't need a dynamo drive sprocket or a shock absorber as the clutch basket had shock absorbing rubbers.
Is it possible that the engine has been fitted with a drive side axle to accommodate the alternator rotor?
Is the primary drive outer cover made from pressed steel or is it a cast alloy one? I can't see from your photo if the primary drive inner case is steel or alloy.

[clive]

According to Thomas's profile its a 52 500 single and I can clearly make out a tin chaincase (time for specsavers Spriddler?), however if the sprocket and cam are fully home I would agree with Spriddler that something is wrong with the shaft. The cam should not be able to "snap over" but there has to be room for the spring. The retaining cup bolts up against end of the shaft. It looks like if it was fitted the coil would be compressed to the point it is spring bound. I suspect the internals may be from a later alternator machine as Spriddler has suggested, it ought to fit the 52 crankcases.