Robert2k,
Check your float levels, they will cause a severe loss of mileage if they're off. The service manual describes the procedure pretty good. Not hard to do at all and it can be done with everything left on the bike too.
Also check your plug color, with that kind of mileage I would expect them to be pretty black and wet, maybe have to drop your mains down a few sizes as well. And sync the carbs when you're all done. Just ride over here in September and we'll get you all set.
