Dang I don't know how I missed this one!!
Cool bike thats for sure! Keep Keith at http://americandirtbike.com/
and Lee at www.atkusa.com
in mind they both deal with the big Rotax and know everything there is to know about them. Along with stocking many parts they are great guys to have saved in your phone. That same engine was virtually unchanged for 20+ years and it is a model of reliability. It a good consensus to change that timing belt (with the OEM Dayco brand only) every season as they are an interference engine. and it is also recommended that you set your valves at a tight .004" NOT .002" like the manual states. If the KTM is anything like the ATK's you'll want to add about 1.5 quarts of oil then run the bike for a minute and add the rest. If you try to just fill the tank up and call it good chances are you'll be low on oil. Lastly that bike "should" have the typical 190W lighting coil in case you want to power a third world country
Can't wait to see more!
Btw that big idle pulley (timing belt) takes a standard sized bearing found at any bearing store so I'd replace that while you have it apart. The little one is something like $90 so hopefully you don't need one of those!