1978 Husky 390AMX fist gear clutch hub

[Colin Jay]

Following the failure of the transmission in my 1978 390AMX at the Oz titles at Crystal Brook, I am in need of a replacement first gear (crankshaft) clutch hub, part number 16 12 550-01.

I have been in touch with Dave Pratt in the US and he has been trying to source one for me for since the Oz titles, but so far has had no luck. Does anyone have either a new or second hand clutch hub that they are willing to part with?

CJ

[PEZBerq]

Whats the problem with the old one?  Dave has one on eBay now Part # 16-12-652-01 that is the same as fitted to my 78 AMX and the correct number from the 78 parts book. It has the long "nose". The number you list must be from an earlier model perhaps? Good luck with the search Col

[Colin Jay]

The number you quote is the clutch drum, 16 12 550-01 is the clutch hub that the clutch actually mount on too.


As you can see, the clutch hub has broken in half across the crankshaft hole.


CJ

[PEZBerq]

Sorry I misread what you said: There are a few auto parts on eBay right now - even a clutch hub (yes a hub - not a drum ) but its not listed with your part number. Maybe it will still work? There are 1st gear springs for your bike at a great price.

Was this failure (cracking at the key) common back in the day? Wonder what the cause was - over tightening, incorrect key, manufacturing defect etc? Good luck getting it sorted.

[Mike52]

Col , I rekon I could weld that no problems.
I have some rods called Hitens that have a high nickle content and work great on stuff like that

[Colin Jay]

Sorry I misread what you said: There are a few auto parts on eBay right now - even a clutch hub (yes a hub - not a drum ) but its not listed with your part number. Maybe it will still work? There are 1st gear springs for your bike at a great price.

Was this failure (cracking at the key) common back in the day? Wonder what the cause was - over tightening, incorrect key, manufacturing defect etc? Good luck getting it sorted.

I have got a complete set of new springs and some new clutch shoes coming out from Dave in the US, so one I get a hub I will be doing a full overhaul.

I have never had any problems like this before (I bought this auto new in 1978) nor heard of similar problems bake in the 70'/80's.  Having said that, I did have one of these hubs crack through the hole where the clutch shoes pivot back when I was racing it in the 70's/80's. Stupidly, a few months ago I was sorting out my box of spare parts and threw the previouly cracked one in the bin, DOH!!

The key was cleanly sheared, and I my suspisions that I might not have had the key fully seated in the keyway in the crankshaft when I torqued down the crankshaft nut, so that might be part of the cause, but I think that old age might have also played its part.

CJ