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What Are These In The Crank Case

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Hi all,

Just been looking at the crank on the 2008 Spare parts book.

Does anyone know what these things are?...and what they do?

Best of balance.

Neo

2009-05-16_214207.jpg

Edited by Neo

Hi Neo

These fit around the crank pin (ie the big end), and are fitted to, and between, the inner edges of the crank webs in order to fill the void and thereby icrease the compressio ratio within the crankcase, leading to even more compression within the cylinder and hence more power!

Although they may not be shown on earlier parts manuals they are certainly fitted to my 2005 290, but I don't think they were readily removable (ie they are "permanently" fitted to the crank webs.

I believe that years ago when tuning Villiers and similar two stroke motors, they used to use similar techniques for stuffing the crankcase void areas.

Portman

It's a "TAPON"!!!! Can't you read espanol! Otherwise exactly as stated by Portman!

Not sure exactly when they started using them, as I don't recall seeing them on earlier years. Could be wrong? :rotfl:

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