have you looked at mine? http://motorbicycling.com/f26/how-i-...tor-13429.html
it'd work the same with a schwinn, and it's pretty easy.
after i read your post, i went outside for the heck of it and checked to see if all my motor mounts were still tight. and they are.
i tightened them up after my first ride ever, and never touched them again. it's been, i dunno, a few months now, and a lot of miles, with no problems at all.