Originally Posted by photolinger
Im just going to comment on the bore sizes right now but that isnt the way to tell each time, ive been corrected on this myself and seen the differences.
Plus one thing to note is the hose inlet is actually larger on an AF than my humongoid KM inlet, so if the case was true, then the AF should have a better draw no matter because of that one part where the KM bottlenecks.
As for the downstem, you guys have to remember, just because it flanges out does not mean its that thick all the way through...
And the AF has a wide open draw, I chose to set my rig up w/ some restriction because im not into it having that big of a draw.
I can't show you pics of the AFs hose port restriction because mine is bored out now but it restricts to just under ~1/4" internally where it bends. It is actually two pieces, the thick walled hose port (where the hose goes) and a tube that is soldered to the end of that, which is the large inlet I think you are referring to.
Here are some pics comparing the AFs internals to my KM.
Starting from the left is AF purge tube and old valve (I built a new one), KM purge tube and valve, AF hose tube (bottom part only, the shiny part is where I cut it from the hose port that I bored out), KM hose port (all one piece).
Here are pics of the leak that came on my purge tube.
Here is a pic of my now bored out hose port (a little over 3/8" at it's thinnest point)
edit: If you flash a light down the hose port like I did in this pic you would be able to see where the restriction starts in the hose port. It's a PITA to bore out because the restriction is throughout the bend to where it is soldered to the hose tube. That's why I cut the tube from the bottom of the hose port so I can get a better angle at smoothing out the inside. It was also to replace the crimped tube, although the neck on the heart limited the size tube I could use.
The flange on the bottom piece of my KM is a separate piece that is soldered on there. It's like that on all other KMs I've seen and also on the AF (the donut piece). The stem tube is a constant ID for the entire length. It is also like this on the AF.
The draw on my AF when I first got it was more comparable to my Mya Bohemian, a little better from what I remember. I should point out that I built a stainless steel stem tube for my Mya which has a ID ~1/32" smaller than the AF's, but the joints and o-rings are what make it more restrictive. The draw after I've rebuilt the internals using larger tubes and bored out the hose port is comparable to KMs, although my World Trophy is still wider.
I should also note that I have not seen the internals for many other KMs so I cannot say for sure it is the same for all other KMs. I'm assuming others with more experience than I are correct in saying KMs are all the same gauge.