As it has been a long time since you flew your REV I and it might be the early bridle version there are two things I can suggest to check real quick.
- Check that the down rods are on the back of the kite, not on the front like a two line stunt kite.
- Check the control line lengths. If you notice that two lines are about 7 inches longer then the other two lines and these are the original lines that came with that REV I then you have the older bridle. If I recall correctly the black sleeved lines are the lower line on both kite and handles and the white sleeved lines are the upper for both.
That's right what John said. The Video that came with the kite had the classic line "black for bottom" (the longer lines go on the top, this is now replaced by pigtails - see below)
My Suggestion would be, contact Rev via this site and get an updated Rev 1 bridle and replace the old one, that way you can use all four lines the same length.
Then as John used to do add pig tails or Leaders as they are called these days. Search on here there will be pictures. I would suggest adding to the top of the handles only, and just keep moving the lines away from the Handles until it flys.
If you can contact a current flyer locally, that would help also.