Hey guys, I've read the wiki, looked at the matrix and read through the official thread. Unfortunately no one seems to have my exact setup or elevation (seems everyone who rides a GS these days lives at or near sea level!). Would appreciate your experienced advice on jet sizes for the following setup:

'89 GS500E (10k miles)
~2,000' elevation (Las Vegas)
K&N RU-2970 "lunchbox"
Stock pipes with Yoshimura R-77 slip on muffler

From what data I've seen, it would seem like 40/147.5 or 40/150 would be the range I'm looking at. As most of the data points are from lower elevations, I was guessing the 147.5 might be the better bet for my ride. Does this sound right? Thoughts? Suggestions?

The answer:  it depends.

You see, jetting is a black art.  Elevation, humidity, temperature all are variables in jetting.  Jetting at 90*F will yield different results slightly than 32*F.

That said, it sounds about right.  I'd buy a 147.5, 145, and 150 main and test.  Do plug chops and that will tell you if you are lean/rich.  Start with 147.5 and go up or down depending on your plugs.  2 washers or 1 O-ring under the needle too.  Set mixture screws 2.5 turns out to start.

Start with your main jet, and work down.