Wear on Clutch Center

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wrecks

wrecks

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I've been distracted from my Norton project but have finally picked it back up over the some time off this holiday. Does anybody have thoughts on where this wear and pitting on the Clutch Center may have come from?


Wear on Clutch Center
 
Looks like your clutch nut locking plate has broke the locking tang and been turning when riding.

Ashley
 
Hardening does not break down on its own accord, it can only be excessive, not done properly or done properly on the incorrect material. It can be broken or worn through by other mating parts though. The issue you have there is contamination causing the corrosion.
 
Presumably, the clutch was removed when the bike was dismantled during the 1980s so possibly could have occurred sometime during storage? Perhaps from a battery spillage that went unnoticed as it looks as if it might be acid damage?

As it's '71 model then the original clutch centre would have been the unhardened type with the 040374 spring/lock washer under the nut and no tab washer.

https://andover-norton.co.uk/en/shop-details/15114/lockwasher-clutch-nut-e6266-a2-373-


The later tab washer 063459 should only be used with the hardened steel washer 063447.

https://andover-norton.co.uk/en/shop-details/16095/clutch-centre-tab-washer

https://andover-norton.co.uk/en/shop-details/16091/washer-clutch-fixing
 
Thanks for all the good suggestions. L.A.B. Is correct, this part was pulled from the bike long ago and has been sitting in a plastic bag covered in oil and grime for 30+ years. I don't know if the issue existed when it was first removed.

Unless there is a good reason not to keep using this part, my plan is to polish it up and use it. It doesn't appear to me that this wear will impact the function of the clutch. Is that correct?

Also, thanks for pointing out the difference in the '71. Should I upgrade to the tab washer setup?
 
wrecks said:
Thanks for all the good suggestions. L.A.B. Is correct, this part was pulled from the bike long ago and has been sitting in a plastic bag covered in oil and grime for 30+ years. I don't know if the issue existed when it was first removed.
Click to expand...

I recently unboxed a box of Triumph parts that I "carefully" stored away in the 70s. When I stored them, I cleaned them, put them in a plastic bag, poured in some new engine oil and turned them every which way until they were completely coated. Then I put them in a cardboard box still in the plastic bag, taped it up and labelled it. I was shocked when I opened it - the parts were destroyed by rust and the bag was not leaking. I guess that sort of thing is why special rust preventive coatings (e.g., Cosmoline) exist!
 
Moisture and humidity in the air is the biggest killer of stored parts even soaked in oil and air tight containers etc most parts that I get are wrapped in paper of some sort with a thin spray of somethink like WD40 or something like that, for some reason paper will absorb moisture better, here where I live our summers are very hot and humid as I write this it 7am and its already 32c and very humid, we also get lots of thunder storms duing our summers and our winters are very mild.

Ashley
 
ashman said:
Moisture and humidity in the air is the biggest killer of stored parts even soaked in oil and air tight containers etc most parts that I get are wrapped in paper of some sort with a thin spray of somethink like WD40 or something like that, for some reason paper will absorb moisture better ....
Click to expand...

Any oil will degrade with time due to oxidation and additive depletion, developing several acid components in the process. The degradation process is fueled by moisture and acids in the air and within the oil itself. Plastic bags may degrade also and deposit acids on the metal surface. Furthermore, there are probably no plastic bags preventing the diffusion of moisture completely.

Best method to avoid long-term corrosion in a moist environment is to soak the component in a potting resin and letting dry before wrapping it in waxed paper. This method was in widespread use in the british m/c industry since WW1. Another method is to store the part dry under vacuum in special bags.

-Knut
 
Casting - really? for a clutch centre. It would have been minimum a stamping or most probably a forging to form the round. The pitted surface you are looking at is the reverse image as the scaling from the forging has been the easiest place for corrosion to attack, it comes away leaving the image you have above. I see this weekly on various forged items, generally not a problem as it is polished or machined out in most cases.
 
Madnorton said:
Casting - really? for a clutch centre. It would have been minimum a stamping or most probably a forging to form the round. The pitted surface you are looking at is the reverse image as the scaling from the forging has been the easiest place for corrosion to attack, it comes away leaving the image you have above. I see this weekly on various forged items, generally not a problem as it is polished or machined out in most cases.
Click to expand...
Yes, cast. Also, notice how off center the center boss is, the machining on center shows that lump of poo should have been culled out prior to machining, but, not a single feck was given, it appears, and it worked ok.
 
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