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Old 12-01-2008, 07:28 PM
RLorange RLorange is offline
Motorized Bicycle Elite Member
Join Date: Jun 2008
Location: Australia
Posts: 127
Smile Piston Skirt mod for improved performance?

Hello Everyone!

I have been trawling through posts about porting and noticed a few things which stand out.

I have successfully removed both the bottom gasket and head gasket in order to boost compression and performance (Not at the same time!). Both should raise compression by the same ammount as they are roughly the same thickness BUT having tried both they are NOT equivalent. Losing the bottom gasket gave me a better boost, my engine could just truck up hills at 3/4 rev (aT WOT). SO I am assuming that the slight port timing difference shifted the torque to lower RPM.

I am intrigued by the Mod which removes an arc of material from the piston skirt which partially block the inlet port during fuel transfer, if anybody has tried this please share your results.

I am going to find a better Silicon than the one I used before to seal up the bottom of the cylinder and make this mod permanent, then I might start to shave some metal from the bottom of the skirt to see if I can squeeze out even more performance. Seems to me to be a safe mod if effective as the skirt has no loading on it.
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