Modifying the 39mm PWK by hoser..

I was running a 34mm carb on the Mossbarger engine and it seem a little flat and 
had a slight bog in the mid range, I wanted to try something new on my Pilot carb
so installed a MAF screen , I put the carb into the lathe and machined a recess into 
the inlet bell of the carb then trimmed the MAF screen to fit, it is held into place with 
JB weld.

A poor picture but you can see the screen.

Heating up the rubber boot so it will go on the larger inlet bell.

Here it is installed, the idea of the MAF screen is to straighten the air before it enters the 
carb after the elbow. The screen is located right under the hose clamp that holds the 
rubber boot on.

Here is looking into the end where the air filter gets installed.

A view from the up stream of the carb.

Here are some aero foils that Kiowa gave me.

They just slide into the carb after the slide.

The little ears stick out to much for my liking so I cut them down with tin snips and smoothed 
out with sand paper  (see next picture for finished product)

I am using this carb until I can find a 36mm or 38mm 39mm is a little big for this engine hopefully
the added restriction of the MAF screens and the volume inside the carb the aero foils take 
up will help fool the engine into thinking it is a smaller carb.

Here is a good thread on MacDizzy's web page that covers  Laminar Air Flow is pretty good
detail. Turbophil  has better pictures of the MAF screen installation.

I started out with a 140 main jet.
The idle mixture seems to be spot on so far (96 degrees out side) the midrange and top 
end seem ok and just a little on the rich side but I have a low to midrange bog that is clutch 
related I have to work out before I can finish dialing in the carb.

More later...