Author Topic: cush drive  (Read 488 times)

Offline mugwump

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cush drive
« on: 05.02. 2016 21:49 »
I'm just about to start putting an Ariel h'master engine back together and because  its almost identical to the A10 I'm forever searching this site and the Ariel site for tips and ideas. I've just read a lengthy thread on here regarding crank end float, shimming and cush drive nut loosening etc. Can somebody tell me why the cush drive nut does not have a lock nut-simples! or am I missing something.

60'Matchy G12
58 AJS 18s
58 Ariel Huntmaster]

Online beezermacc

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Re: cush drive
« Reply #1 on: 05.02. 2016 22:27 »
.... because the nut tightens up against the crankshaft sleeve so the nut is basically a locknut holding the sleeve firmly on the crankshaft. There is a common misunderstanding that the nut should only be tightened sufficiently to compress the spring but actually the nut should be fully tightened, at which point the spring tension is correct. The nut has slots so it can be finally tightened with a chisel, I know this sounds disgusting but this method of shock-tightening is the most effective way of achieving a firm grip through the components which are intended to be locked together. There should also be a lock washer between the nut and the sleeve which is a bit difficult to peen over because you need to poke something through the spring to achieve this. There should be a hole for a split pin through the crankshaft - this is only as a bit of security to prevent the nut coming off completely in the event of it working loose. Some people think that once you have screwed the nut up enough to get the split pin in, job done, not so! The nut must be locked up against the crank sleeve. Hope that explains it.
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Offline mugwump

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Re: cush drive
« Reply #2 on: 05.02. 2016 22:33 »
Thanks, that explains it perfectly. I now know why my M21 used to clunk and rattle so. Many years ago.

60'Matchy G12
58 AJS 18s
58 Ariel Huntmaster]

Offline duTch

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Re: cush drive
« Reply #3 on: 06.02. 2016 00:06 »

 
  *eek*
Quote
The nut has slots so it can be finally tightened with a chisel,
....can we call it a drift...? less stressful *smile*...or make a tool with a hex to use a (torque)wrench

I found a washer the right thickness to fit behind the split-pin against the nut as 'preliminary extra security' seems to float ok.
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia