You can get an inexpensive motorcycle jack at Costco, Walmart, Sams Club, or most other discount warehouse stores for around $50 to $75. Most are rated for 750 to 1000 lbs and have tiedown locations. Some also have wheels so you can move the bike around while it's up in the air. (very handy)
I feel that "makeshift" jacks are inherently unsafe.
It's your bike and your ass, so be very careful! :2tup: