During combustion in a side valve engine there is a flow of gases from the valve pocket to the cylinder. If a flat top piston extends above the top of the cylinder, I would be concerned about the affects of side loads on the piston that may result from that flow.
Kevin
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1916 Indian Powerplus - future Cannonball prospect
1964 Triumph TR6 - 50 year ISDT Tribute
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OK thanks Kevin, that makes sense. It would be interesting to know what sort of loading that would put on a piston although I doubt anyone has the answer.
John
1916 Indian Powerplus - future Cannonball prospect
1964 Triumph TR6 - 50 year ISDT Tribute
1969 BMW R60US
KTM 640 ADV - Guzzi Centauro - Husky TE510 - other stuff
"Yoicks, and away!" - Daffy Duck
Kevin
On the later Indian Chief “74” standard motors, the pistons stop below the top of the cylinders. On the “74” Bonneville motors, the pistons stop even with the top of the cylinders, as the pistons are different. On the “80” motors, the pistons stop above the top of the cylinders, as the motor is stoked, using the standard pistons.
Burgie
1916 Indian Powerplus - future Cannonball prospect
1964 Triumph TR6 - 50 year ISDT Tribute
1969 BMW R60US
KTM 640 ADV - Guzzi Centauro - Husky TE510 - other stuff
"Yoicks, and away!" - Daffy Duck
I would say standard 74 chief pistons ,at least 34-53 , come to top of cylinder,80and Bonneville pop up,both requiring a relieved head.
Tom
1916 Indian Powerplus - future Cannonball prospect
1964 Triumph TR6 - 50 year ISDT Tribute
1969 BMW R60US
KTM 640 ADV - Guzzi Centauro - Husky TE510 - other stuff
"Yoicks, and away!" - Daffy Duck
All flat.
Tom