Norton Atlas Piston NOS +020

A pair of them would be a lot more useful. !

With a good balance job, higher comp pistons give more go, and don't necessarily have the bad vibes either..
 
I do not think a pair can be found. After a diligent search, I did find a pair about two years ago, but they turned out to be slightly different, and one had the notorious slots that are known to shuck the crowns. The dealer (?) in the UK was gracious enough to restock without a fee.

If someone should have some NOS stock, the value would depend on how bad you want original pistons. I would say 125 $US each would be reasonable.

Slick
 
Re; “I do not think a pair can be found.”

Too right they are about as rare as hen’s teeth :!: :? :cry:

Yes it has the dreaded vertical slots in it and these I think are made in Germany – but where will you find another :?:
 
Bernhard said:
Re; “I do not think a pair can be found.”

Too right they are about as rare as hen’s teeth :!: :? :cry:

Yes it has the dreaded vertical slots in it and these I think are made in Germany – but where will you find another :?:
Click to expand...

The pair I mentioned above was obtained from F W Thornton Co in the UK. If you only need one, you have a 50-50 chance they still have them, and the side you need is without the slots.

Good lunch in your search.

Slick
 
Bernhard said:
Re; “I do not think a pair can be found.”

Too right they are about as rare as hen’s teeth :!: :? :cry:

Yes it has the dreaded vertical slots in it and these I think are made in Germany – but where will you find another :?:
Click to expand...
It's not vertical slots to be aware of but slots cut around under oil control ring..
 
texasSlick said:
Bernhard said:
Re; “I do not think a pair can be found.”

Too right they are about as rare as hen’s teeth :!: :? :cry:

Yes it has the dreaded vertical slots in it and these I think are made in Germany – but where will you find another :?:
Click to expand...

The pair I mentioned above was obtained from F W Thornton Co in the UK. If you only need one, you have a 50-50 chance they still have them, and the side you need is without the slots.

Good lunch in your search.

Slick
Click to expand...
I think they have it: http://www.classic-motorcycles.co.uk/cg ... d=&Start=0

Fritz
 
Bernhard said:
These are NOT the 7:5 to 1 pistons but high compression 8:5-1
Click to expand...
Isn't it possible to mill the piston down to reach an acceptable compression?

Fritz
 
bad_friday said:
Bernhard said:
These are NOT the 7:5 to 1 pistons but high compression 8:5-1
Click to expand...
Isn't it possible to mill the piston down to reach an acceptable compression?

Fritz
Click to expand...

i do wonder if the original concave pistons were done that way. In theory, the metal removed is not in the structural wall where the strenght to resist centrifugal force is necessary, so milling might work, but I would be afraid to risk it.

Slick
 
A lot of pistons have a bar or even 2 cast in underneath the crown, to give it some strength.
You'd have to wonder about taking too much metal out of the crown...
 
Once again, NOT the 7:5 to 1 pistons originally fitted to the Atlas :!: :!: :shock:
 
No, but do they start somewhere that they are the D-E-E-P-L-Y concave/dished 7:5 -1?
Or even the slightly concave 8:5-1?
 
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