If you do it for the troops bikes then I wouldn't advise that route. Dark Angels are still a 6th ed codex currently and will likely get an update at some point for 7th ed. That update will almost certainly take the 'troops' out of bikers like seems to be the general trend at the moment of removing anything that 'alters' a units battlefield role. Just look at Blood Angels they lost assault troops. Orks don't have any that change their battlefield role now. And I don't think Kor'sharro Khan changes bikes anymore and he was 6th ed Space Marines. (Don't quote me on that though; don't have my Codex to hand and not 100% sure if he does or not). And I do know orks don't change roles anymore and they were the first 7th ed dex.