[How to repair piston?]

What about a countersunk rivett?

No heat, no glue. 

Just a pair of thin metal sheets, one outside, embedded in the concave hole, one inside for fixing the rivett.

[How to repair piston?]

17 minutes ago, brian0304 said:

Is it that special / rare that’s it’s worth the gamble of either ruining the piston or damaging the engine if the repair weakens it ? If not, buy a new one and stick that one on eBay 

Yes. You are right. I will not start any try if I am not absolutely sure. In fact, I have  bought a new pistón, but I own several sherpas and, may be, I could test a repair.

[How to repair piston?]

Ok. Now I understand your idea, and It sounds fine!

[How to repair piston?]

2 minutes ago, djr said:

perhaps making a plug that fits tightly - then drill and pin ?    or drill and screw ?    or glue if you can find something that will withstand high temperatures ?

Mmmm. This sounds interesting. But I dont understand "drill and pin" or "drill and screw". I understand the words, but I dont visualize the idea. Could you attach a drawing?  

 

Thanks before hand

[How to repair piston?]

43 minutes ago, brownie001 said:

Hi, why would you need to close it off ? If there are no ports in the cylinder matching, it won't do any harm.

This central window must be closed because if drilled, the gas goes back to the carburetor. All depend of the transfer diagram. This piston (with central window) would work on a Bultaco pursang, but not on a sherpa

[How to repair piston?]

Hi all.

I would like to know if is possible to repair this piston. The central window port is a mistake, and I need to close it. 

How could I save this piston? Welding? Glueing with metal adhesive? Any other idea? Thanks in avance.