You're right, there isn't much room; that's probably the toughest part of the whole thing, but still manageable. I didn't touch the radiator cover; only had to remove the side covers just to get to the wiring. If you turn the bike so the front wheel points to the opposite the side that you're installing you will have a bit more room to get a tool in there (ex: if you're installing the left signal, turn your bars to the right). I finger tightened it and then was able to squeeze an open end box wrench in there (I can't remember the size). The mounting adapters are plastic so be careful not to overtighten. Blue loctite can be your friend.how'd you tighten the signal stud nut? did you remove the entire radiator cover and tighten them off the bike and then re-attach? Because there's not much space when the covers are in place.