Yeah, this is on my 'berg. But, I've had the same problem on all my bikes (in the last 2 years- TE610, KDX220, and Scrambler... then there was a long gap with no bikes. Not sure if I had this problem 25 years ago, though).
The axle is always clean and well-lubed. I use a huge screwdriver as an alignment tool, similar to the Long John thing. Sometimes, I'll use a tire iron under the tire for a little leverage.
I may try and find an aluminum tube just slightly narrower than my axle, but with a tapered end. That way, I can use it for alignment, and hopefully the tapered end will fit in the end of my axle to help guide it all the way through. (The tip of the screwdriver was slightly wider than the hole in the end of my axle.)
I realize it's just a matter of getting everything aligned- but that's the problem.
Edit - just noticed the Long John instructions... sounds like a pretty good tool.
1989 NX650 (for sale