Don't claim that this will fix the problem but the instructions clearly state that you should cut 5 mm off of the pull cable sleeve. So it sounds like you didn't install it correctly.
As I recall, the R1 and R6 throttles mentioned earlier used to run about $12 but they're now about the same as Hairy R's. The R1 doesn't require any cutting.
on the subject of the 5mm cut on the cables
just for the record the hairy rs i got is gsxr1000 k5/k6 was new in unopened box and fitted fine with no cutting of outer cables, the instructions that came with it gave no mention any were about cutting outer cables..
if i was to start cutting outer cables it would be pointless as they dont need any cutting, id just be taking up even more slack with the cable adjusters,
so to clear a point up, there is no cutting needed on the gsxr 1000 k5/ k6, i can speak for other bikes though,
although i advise making cable guides on the edges of the hairy rs part like i am