won't idol w/o choke. but runs fine when riding it. also will not go in to high range, but when tries it grindes

 

Your idling problem sounds like a restricted pilot jet. Tell tale sign of only idling with the choke.

The Hi/Lo gearbox problem you are having could be a few differerent things. Take the cover off and check into it. It's real easy to get to, doesn't have any complicated parts inside, and above all, used parts to fix it are abundant!