Ninja sticker came off with a finger nail and a hair dryer... then some Eucalyptus oil to clean the gunk off. The Kawasaki decal is clear coated over, so unless you what to redo your tank, or someone knows a secret trick, its staying there.
Same as felix... Use a hairdryer to heat up the glue and then gently (read: immensely slow) peal it off.
Be careful not to overheat though, it could damage the paint.
Best result is when the bike is new (fresh glue, no colour differantiation)
As said, the kawasaki logo is painted and non-removable.
To get excess glue off, use a soft detergent and have lots of patience. Don't rub too hard, it will scratch the paint.
I found a site WWW.DOWNAT70.COMhttp:// that has decals that will cover over the clear coated Kawasaki logo on the tank. They don't show any available for the 250r, but I bought the ZX6 ones & with a little bit of time I was able to cover it up & I think it looks pretty good. I'll will try to post up some pics later to show how they turned out.
t1gawa - no I didn't buy the $25 set. If you look at their order form you can just buy the "kawasaki" tank decals & the "ninja" decals. They both come in a 2 pack for $10 each plus shipping so you can save $5 & not waste the engine size decals. I will tell you that the fit is not the same on the "kawasaki", it does have to be cut & each individual letter has to be put down seperately, but it is SUPER easy if you take your time. Took me all of 30 minutes to get it how I liked it. ;D