Does anyone out there have a completely standard ski that is considering this? I mean really. Manufacturers are looking at jetting in a completely different way, they are more interested in fuel efficiency and lower emissions than anyone on this site so of course that are gonna use small pilots, just big enuff that it doesn't run lean on acceleration and that's it. If you're running 44's or bigger the Pilot is pretty massive and therefore close to the Main Jet size anyway (120 Pilot, 137.5 Main as Redtro states). Swapping them would prob do just what Wax says, better punch off the line on a modded ski. While the engine is running, you can pour fuel into the carbs, basically half filling them, grab the throttle and it just sucks it in and goes crazy so really, too much is way more than a 1.375mm jet is ever gonna be able to deliver So, so long as you're not starving it up high i.e the total size of both jets added together (in laymans terms, one would want to do high speed testing, plug chops of course) you should see some sort of difference. Worst thing I can see happening is it loading up if you let it idle for a while and using more gas for sure. 38's will be a different story as the pilot is so much smaller, still, I do know of ppl running reasonably large (90+) pilots and smaller mains and getting the same sort of effect..
If you want some excellent information on tuning and an explanation of how the carbs work read this. http://www.greenhulk.net/forums/showthread.php?t=65275
