My trip to APT (Home of the SmartCarb)

[rablack21]

Update 11/24/15:
Just thought I would share some interested info with you guys. So I finally got some information about the dyno runs from my trip. I (and Corey) got buys and just never got around to gathering the data. I don't have the dyno charts yet, but will get them when Corey gets some extra time. Here's the info I do have at the moment. I found it interesting so I thought I would pass it along.

Here are the peak hp numbers:
363 engine w/ 38mm Smart Carb - 57rwhp
363 engnie w/ 40mm Smart Carb - 61.5rhwp

These numbers were both with no airbox/filter and an old dented fmf fatty pipe (had to install an oxygen sensor, wasn't drilling my good TRX 5B pipe).
What surprised me was not the peak hp, but the difference in hp output between the 2 carbs. I didn't expect it to be a 4.5 hp difference. Before some of you experts jump in , yes I realize that the difference between the 2 carbs would yield different results depending on the setup of the engine. Anyway, I thought you guys might find this cool as well.

[JesseA420]

These numbers were with an old dented fmf fatty pipe

[Jerry Hall]

Update 11/24/15:
Just thought I would share some interested info with you guys. So I finally got some information about the dyno runs from my trip. I (and Corey) got buys and just never got around to gathering the data. I don't have the dyno charts yet, but will get them when Corey gets some extra time. Here's the info I do have at the moment. I found it interesting so I thought I would pass it along.

Here are the peak hp numbers:
363 engine w/ 38mm Smart Carb - 57rwhp
363 engnie w/ 40mm Smart Carb - 61.5rhwp

These numbers were both with no airbox/filter and an old dented fmf fatty pipe (had to install an oxygen sensor, wasn't drilling my good TRX 5B pipe).
What surprised me was not the peak hp, but the difference in hp output between the 2 carbs. I didn't expect it to be a 4.5 hp difference. Before some of you experts jump in , yes I realize that the difference between the 2 carbs would yield different results depending on the setup of the engine. Anyway, I thought you guys might find this cool as well.

My experience has been that these big bore cylinders need larger carbs than what Mikuni or Keihin offers in a compact design.  We bore the 38 mm and 39 mm carbs to 41 to 42 mm and that is still not enough.  The VM 44 Mikuni just not fit into the space confines very well because of its height.  But the engines can use the increased air flow that comes from carbs in the 44 to 46mm range.