Gear Selector Drum Damage?

[IanW]

I am starting a rebuild on a motor with about 30K kms. I noticed that the gear selector drum shows some discoloration at one end. It looks consistent with overheating, which is odd because this drum does not rotate much. There is a small amount of end-play in the assembly which I assume is normal.

Any ideas how this discoloration could have happened and if it is important?

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[drewpy]

I am starting a rebuild on a motor with about 30K kms. I noticed that the gear selector drum shows some discoloration at one end. It looks consistent with overheating, which is odd because this drum does not rotate much. There is a small amount of end-play in the assembly which I assume is normal.

Any ideas how this discoloration could have happened and if it is important?

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I think you would be fine with that.
I had some blueing on a Gilera fork gear selector and the consensus was no issues (and there wasn't)

 

[xschris]

They all look like that. It's from heat when that part of it was made.

 

[IanW]

Thanks for the responses. Good to know.

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[IanW]

Thinking more about this, if this happens to all the drums than maybe it is a product of the original tempering of the drum along the selector area to increase hardness. This would leave the end more ductile so it has has little axial give when shifting. Of course I maybe completely over thinking this...

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