Here's a video to explain how to change them. Maybe an hour start to finish to replace the jets.

http://www.youtube.com/rycamotors#p/u/6/rFFuF9QZ4IM

I don't know about doing damage running lean. We'll have to leave that question to the pro's here.

Thanks for the info and video link!

Do you guys take the whole carb off everytime you rejet? Or can I just do it while it's on the bike. Doesn't seem like there is much to changing the jets themselves really. Take off the bowl and unscrew.

Any problem if I hold off on the spacer mod for now, or should I suck it up and do that now too.  

I'm in the pacific northwest, near sea level, so I think I need to go much richer. Maybe I'll start out where the Ryca guys jet in LA.

55 Pilot / 155 Main Jet.

I just recently did both the spacer and the jets. As stated, changing the jets and the spacer are both easy, the only real problem is getting the screws out without buggering them up. That said, they are much easier to reach and handle with the carb off. I was hesitant at first to remove the carb but that is actually very easy, just remove the battery box first and it slides right out. Oh yeah, replace those screws to the bowl and the top of carb with hex screws.  Read up in the tech section on removing the screws (they have loctite on them) many helpful ideas. I loosened them with a small hammer and small punch then vise grips.

and put a towel over the starter cause if you drop something it'll be hard to find.

Well, after a trip to Ace, I was able to get a 90 degree angled screwdriver, which enabled me to get the bowl off the carb. Without that, it was pretty much impossible to get it off. I was then able to remove the large jet fairly easily ( 145 ). However, I can't get the smaller jet out yet. I have a small screwdriver, but I think it's too small, and I don't want to strip it.

I couldn't find a stubby screwdriver in a medium size, so I can't get the smaller jet out. If I keep pushing it, I know I'll strip it and make it even harder to get out. ( I imagine tapping on it might not be a good idea )

Looks like I'm going to have to either rotate it or take it off completely. Sigh. I guess that means I need to drain the tank and take it off.

Frustrating, because I was only a small jet away from swapping them out and being on the road again.

Well, my bike is officially in pieces. I pulled the carb. Going to be crazy putting it all back together. I just hope I can get this jet out. Not sure what will happen if I can't get it out.

As I said before, I would have done the spacer mod later, and only if needed. Doing multiple things to a carb all at one time can cause you lotsa grief if luck isn't w/ you.