clutch hub fouls inner chaincase

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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clutch hub fouls inner chaincase

Postby Stephen R » Wed Sep 11, 2019 12:36 pm

I'm reassembling an 18CS with the pressed steel primary chaincases, the back of the clutch hub ( the locknuts on the spring pins) rubs the chaincase inner. I cant pack the clutch out because that would rub on the gearbox output shaft, so what has hAppened/ do I need to shorten the spacer to bring the primary cases closer in to the engine and away from the cluch hub?


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Re: clutch hub fouls inner chaincase

Postby bjorn » Wed Sep 11, 2019 9:55 pm

Hi Steve,
I believe it would be helpful if you gave some more info on the machine. From your description of the clutch it would be an AMC item? So 1957 model or later? Are the motor/gearbox/clutch all from the same year? Has it been previously assembled/running without the clutch to chaincase clearance problem?


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Re: clutch hub fouls inner chaincase

Postby 1608 » Thu Sep 12, 2019 2:32 pm

It could be the hub centre ( vanes ) wearing on the end and allowing the hub centre to chafe the inner chain case. This is normally due to the 60 yr old part being constantly tightened/over tightened causing the splines to wear. I had to renew mine because the hub centre had a groove worn on the end from contacting the gearbox input shaft. Hope that makes sense!

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