I've heard that the Bridgestone Battleax BT090 is a good replacement for the stock IRC tires that come on the Ninja 250R.
Does the D-tracker come with the same IRC tires as the Ninja 250R?
Here's what the description says: "Refined by using the latest technologies from Bridgestone, the BT-090 is perfect for aggressive riding on both circuit and street. The rigidity of the tyre induces better contact feel in corners, especially for slide control during races. The new compound and pattern offer improved grip and handling in both wet and dry conditions, with better high speed stability and anti-shimmy performance ensuring a smooth ride."
Not hard to find here in Bangkok, easily shipped. A lot of guys up the size from the stock 130 to 140 or even 150 for looks, though performance impact is debatable. Here's a good before and after pic for comparison:
(I'm not sure these are Battleax tires...)
Happy Trails!