pistons - the shape of things to come

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jseng1

jseng1

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Auto desk image of weight efficient piston. Note the internal skirt struts. I'm not promoting this as a potential Norton piston option - just showing where things may be headed (never mind the missing oil ring).
pistons - the shape of things to come
 
In the old days when I earned 10 pounds per week, a Manx piston cost 30 pounds. However 'quality does not cost - it pays'. I have always liked Mahle pistons, but their online catalogue is a horror.
 
I saw these kind of pistons at a modern bike shop.

The engines produce extraordinary horsepower.

But require oil changes every 15 hours and new pistons every 100 hours or so.

Not really suited to me. Except perhaps racing.
 
johnm said:
I saw these kind of pistons at a modern bike shop.

The engines produce extraordinary horsepower.

But require oil changes every 15 hours and new pistons every 100 hours or so.

Not really suited to me. Except perhaps racing.
Click to expand...

Ultra short pistons as shown in the 2nd post are not suitable for a Norton. Those are high maintenance watercooled pistons for racing only.
What I want to bring attention to is the struts to the skirts as shown in the first post.
 
I would think that such pistons were designed to run with very short strokes; over square is the new normal...No?

Best.
 
The special JS pistons and rod combo....I would like to see that style of piston for a standard motor. A huge bonus is that the drag of the rings is so much less than the standard set up. And how long do these very thin rings last?
 
seattle##gs said:
The special JS pistons and rod combo....I would like to see that style of piston for a standard motor. A huge bonus is that the drag of the rings is so much less than the standard set up. And how long do these very thin rings last?
Click to expand...

I have 50,000 miles on the thin rings and they still have excellent leak down sealing with no smoking. The longer rod is what gives the JS pistons an advantage because the pin boss can be moved closer to the rings and thats how you reduce weight (by eliminating material between the pin and the crown as with modern bike pistons - but don't shorten the skirt too much for Nortons). The same piston as the JS lightweight piston can be stretched to fit the standard length rod but then you have a heavier piston. The pistons from left coast racing are the same as mine but are stretched to fit a stock rod. Actually its the other way around - first there was the Left coast piston and then I shortened that basic piston design to make it lighter - thanks to help from Ken of Left Coast racing. You can get the Left Coast racing pistons from Ken and they will fit the stock rods. Left Coast racing pistons were also sold through Steve Maney. Ken goes by the moniker "Lcrken" in this discussion group.
 
My KTM 790 Duke pistons are like that, which is how it makes 98bhp and phenomenal torque vibe free from a twin cyl. Would be great to see similar in a Commando mind.
 
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