Piston Skirt mod for improved performance?

Discussion in 'Motorized Bicycle General Discussion' started by RLorange, Dec 1, 2008.

  1. RLorange

    RLorange New Member

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    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.
     
  2. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Be careful! Raising the compression also raises the engine temp. (It will probably hurt most when the summer comes!)
    Keep us posted & post pics!! (^)
     
  3. trackfodder

    trackfodder Member

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    You are right about the low end power gain. You dropped your ports so it retains combustion pressure longer and the increased c/r probably helps, but of course the top-end power suffers KW
     
  4. RLorange

    RLorange New Member

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    I was reading that the top end should suffer but I didn't notice this. Then again I don't usually let my engine hit the high revs for long. Being able to power up hills is far more valuable to me. On Main hill I ride It gets up at maybe 25kmh with the mod at WOT and only 20 or a bit less without the engine will never max out RPM wise on these hills.
     
  5. RLorange

    RLorange New Member

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    Also in response to Venice Boy, I have solved my engine heat problem by using an oil additive treatment called Bi-Tron. It is a 2-stroke specific oil product which is unique in that it is 100% pure petroleum (Mineral) derived Parrafin based oil which is treated to make parts of the oil molecule polar which then stick better to metal in effect giving the oil surface tension sticking properties like other polar fluids. This sticks to a clings to all components of the metal it comes in contact with but also sticks to the regular 2-stroke oil. The reduced friction is remarkable and my engine never gets too hot even after a long slog on hot days. The polar oil leaves a layer coating the metal which also seems to make the fuel flow more sticky so it has the same effect as polishing the ports.

    Really great stuff. I highly recommend it!! especially if doing any kind of MOD
     
  6. mechanickid

    mechanickid New Member

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  7. 2door

    2door Moderator
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    Where is it available? Haven't seen it anywhere here yet.
    Tom
     
  8. mechanickid

    mechanickid New Member

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