words of advice on prepping for vinyl dye...
for best adhesion and over-all performance, the professional way to prep.
hot hot water
dish soap (I like joy, not sure why, it just seems to work best)
grey scotch-brite pad
clean rinse water
mix a few tsp of dishsoap into a couple gallons of hot water, and lightly scrub the vinyl until the water runs off uniformly, with no beading effect. after the entire surface is well scrubbed, rinse with clean water and let it air dry as long as possible. Any moisture in the vinyl will make the dye fail prematurely. dust coat it, then follow with a few light coats until you get uniform coverage.
follow the can instructions for coating, if they have any.
A lot of the high end dyes are nothing more than laquer based paint, thinned out. Some are just uncatylized base coat, like Omni AU (MBC). That's what "cars" uses for their reproduction color matched upholstery. You can smell it when you take the seat covers out of the box.
I have been using "cars" upholstery for a while and never had any trouble with color rub off. Of course, since there is more leg movement, and less surface area to sit on, I am sure that motorcycle seats would be the ultimate challenge for any vinyl dye system.
Good luck,
