My First Strato Porting Job

[Chris-PA]

This saw has been working great and I've been quite happy with it, but I have had trouble getting the air filter to seal to the air valve. Basically, they blew the design of the filter - it does not seal. It look like maybe they intended some kind of foam seal or something, but just left it out. Here is the issue - the filter must seal to both the carb inlet and the air valve (here I've used a flat file to smooth the air valve surface):


Using the bottom half of the filter you can see the gap - about 0.075":



I've tried some adhesively backed foam strips, but there is not a lot of surface to attach them to, they come off and they tend to block the air inlet. So I decided to make a shim on the 3D printer:


Here there is a bit of a gap, but the filter is flexing without the top half attached:

Now, in the picture above you can see that the filter intruded in past the shim (and the air valve rim) and is restrictive. So I trimmed it back:

And here is a blurry shot of the filter with the air valve held open:


I'm interested in seeing how it works.

 

[redfin]

Mr Chris, I truely appreciate your attention to detail and passion of accuracy.

 

[Mastermind]

I agree.

 

[Chris-PA]

Thanks guys - in reality I've been looking for excuses to make some parts with the printer, and this one was simple enough to do.

There are some others I've been thinking about, but I can't find time to design them. Air filter adaptors are pretty well suited to the materials.

 

[Full Chisel]

Excellent thread. I know nothing about engine building, porting or two stroke theory but this is a fascinating and information packed read(maybe dense is a better word for my experience level!). I can easily see your enthusiasm for what you are doing, keep up the good work!