First off, thanks for all of the tips, tricks and resources. Now here's some details, many which agree with previous posts, but I'm going to include as much as possible to help anyone else attempting this:

The Bike: 2007 GS500F, Yosh slip on, K&N drop-in (not lunchbox), new NGK Iridium plugs. Northern WI, ~600ft elevation.

The jets: After much research, I basically went with the Wiki. 20/62.5/142.5, no washers. 3 turns out (boy, it seemed really loose, but we went with it anyways).

The results: Far greater powerband, especially from ~8k - 11k. Better throttle response, and no lagging when RPM's are falling. Also, this was my first bike, so I thought nothing of it when the exhaust spit and sputtered when I downshifted, primarily to engine break. Every ounce of spit and sputter is gone now, replaced with a smooth decrease in RPM's.

The tips/experience:
1.) This forum can't stress enough to use a manual impact driver on ALL of the screws on the carb. messed one up without it, but made it work, and went right back to using the impact on everything.
2.) Getting the airbox back in was not fun at all (as mentioned to me on one of my previous posts). Patience, some wiggling and moving some hoses out of the way was absolutely necessary.
3.) Label your hoses, even if you think you will remember. The are so many breathers, etc. that it is difficult to keep track when reassembling.
4.) Was easier to work with after tank was drained.
5.) Simple things, like ample lighting, keeping a fan going for ventalation, use carb cleaner to splash out any sludge in carb, have plenty of towels, etc. All basically "why nots."

I'm sure there's more to add, but all in all it was an excellent experience with fantastic results. I obviously haven't driven enough to determine the impact on mileage, but the bike itself just seems "healthier" to the point where I'm sure the trade off will be worth it.

Thanks again all - now time to enjoy the twin!

Quote from: axentz on September 16, 2009, 09:08:50 AM
The Bike: 2007 GS500F, Yosh slip on, K&N drop-in (not lunchbox),

20/62.5/142.5

This seems very rich..

135 would be where I'd start with that setup.
Cool.
Buddha.