Chrome bores.

[Stevex]

When did Guzzi stop using chrome bores?

[Testarossa]

See https://wildguzzi.com/forum/index.php?topic=106818.0

[Antietam Classic Cycle]

When did Guzzi stop using chrome bores?

The latest Guzzi I've seen with chrome bores was a '79 850-T3.

[chuck peterson]

850cc T3 was a transition model, some did some didn’t. Probably used up all the chrome bore T3 cylinders they had on hand to clear inventory then switched I imagine

Convert, the first 949cc motor, was not, as was the G5 that followed was not. Nickasil, Nigasil, whatever it’s called was/is incredibly durable

So it’s not so much when but what model of a lineage

Magnets help sort the chrome vs iron...I forget which

Correct me if I’m wrong

[Antietam Classic Cycle]

850cc T3 was a transition model, some did some didn’t. Probably used up all the chrome bore T3 cylinders they had on hand to clear inventory then switched I imagine

Convert, the first 949cc motor, was not, as was the G5 that followed was not. Nickasil, Nigasil, whatever it’s called was/is incredibly durable

So it’s not so much when but what model of a lineage

Magnets help sort the chrome vs iron...I forget which

Correct me if I’m wrong

In my experience, all US market T3s had chrome bores, they were replaced by the T4 (in markets other than North America) which had Nigusil.

The 949 round-fins all were iron liner until '80-ish when they switched to Nigusil. 

Chrome is non-ferrous, so a magnet will not stick.

[wirespokes]

I can't remember it that way because Nigusil - Nickel and Silicon - aren't ferrous either, but they're slightly magnetic. Makes no sense to me so I haven't figured out a way yet to remember how that goes.

[Antietam Classic Cycle]

Nickel has ferromagnetic properties. https://fractory.com/magnetic-metals-non-magnetic-metals-with-examples/

[wirespokes]

Well, that explains it! Thanks Charlie! 

[Dave Swanson]

My 1980 T3 California has factory Nigusil barrels.  I believe it is one of the earliest MGs to have it.