High compression pistons for a Dommi 500 plus 20

Chris

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Hi

Looking at pistons for a Dommi. Basic old fashion sprint bike road class.
Plus 20 9.5 to 10.5 would be ideal. I remember a batch of very high compression pistons probably 11.25 to 1.
I know Jim does something,
Red Lizard sell jp pistons 9.5 ref 18548 plus 20.
Any others?
Please feel free to chime in.
 

texasSlick

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I ran 10.5 :1 CR in my Atlas since the late 60's. Back then, 103 octane could be found at any pump. Now days, with fuels available, I have gone down to 9.0:1 CR to avoid the pings, or to avoid octane boosters.

I would limit CR to 9.5 max for a street bike running pump fuels.

Slick
 
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10.5 pistons for the 500 Domi are I think, virtually unobtainable now, but if you overbore and use 600/650 10.5 : pistons ……
 
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Oct 16, 2016
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Hi

Looking at pistons for a Dommi. Basic old fashion sprint bike road class.
Plus 20 9.5 to 10.5 would be ideal. I remember a batch of very high compression pistons probably 11.25 to 1.
I know Jim does something,
Red Lizard sell jp pistons 9.5 ref 18548 plus 20.
Any others?
Please feel free to chime in.
Chris a few years have passed, did you ever find an answer. I ask as I have a Dommi project, domed pistons in it, no idea of CR.
 

Chris

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Hi Steve's
Its my mate John's sprint bike. We found some 9 to1 & he has been running those. However at this moment in time he is welding the pistons! So far he is very happy with how it's going. I will ask him to take some photos.
 
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