On my "new" WR which I rescued from it's previous owner, I'm going over as much maintenance as I can, pre-season.
I'm pretty sure he used an impact on the drain bolts, if he in fact ever used them.
I've been hitting ALL the fasteners on the bike with PB and Deep Creep, but the header bolt is not co-operating. I can't get an allen key socket in there, and the 4" key just twists. I've tried with the nut on the other side of the flange both loose and tight, and given the bolt a few good raps with a punch from both sides.
Anyone have a good trick to deal with this? I've searched, and welding a nut on there seems to be the only thing mentioned.