As others have said, it is fine to take Hyperdrive, or any other fat burner for that matter, while bulking. I also agree that Hyperdrive is the single most potent component of the Tri-lean system, although I love Special Tactics too. I use both of those right now, and I'm bulking.
I am starting to think that fat burners are best taken while bulking, and less necessary when cutting. It makes sense when you think about it. In an anabolic state the increase in fat oxidation and/or downregulation of fat storage enzymes (depends on MOA of the product) provided by a fat burner will help you limit fat gain, and will have a negligible impact on muscle building. In a catabolic, calorie-deprived state, it can be argued that a fat burner will actually enhance catabolism of muscle as well as fat. Even if this only occurs on a low level, every ounce of muscle is precious to a natural athlete. Of course, I am still letting my thoughts on the matter mature as I research the ideas further. I definitely think fat burners are a-okay while bulking though, no doubt about it.