Chainsaw Repair

   These are a very well designed saw, and dependable in the woods, but seem to be lacking in performance. They use a full skirted piston  with windows, and all transfer flow must pass through these windows, to get to mid fed lower quad transfers. The original piston is also domed. I found that a Husky 268 piston makes a good replacement, it is slab sided but not windowed, and has enough skirt length and width to allow widening of the EX port. It is also much lighter, and has a flat top, requiring a lot of squish band and combustion chamber work.
   Here is the saw stock.
https://www.youtube.com/watch?v=hIIFMow_69I&feature=youtube_gdata_player

   And here it is after mods with the same untouched chain.
https://www.youtube.com/watch?v=AMlxrbizvo8&feature=youtube_gdata_player

    Thanks!

   In order to help out the restricted transfers, I added fingers at the end of the bridge.

   I have the 670 piston in the scrap bucket, I will get pics and measurements of it and post the results. I do know that the  268 piston was around .080 taller, as that is how much material I removed from the squish band. This brought compression up to 250psi, so I had to remove a little material from the combustion chamber. Comp is now 190psi after about two gallons of gas.

   The fingers are connected to the intake side uppers.

   I tried to attach a photo, it shows up when I look at the thread, hope everyone else can see it.

   The fingers are connected to the intake side uppers.

   I tried to attach a photo, it shows up when I look at the thread, hope everyone else can see it.

I can see them and when clicked on pic it enlarges to giant size. Like this.

http://chainsawrepair.createaforum.com/index.php?action=dlattach;topic=4526.0;attach=10906;image