If you're into the expense of new triple trees, then go for it! Me, I'll straightne mine if they're slightly out. I believe it's possible lower triple trees have gotten tweaked due to incorrect steering head bearing adjustments, rather than accidents. After a year being tweaked, and baking in the sun on a hot afternoon, it's taken a new set.
But if the tubes are bent, for sure take care of that first!
Excuvator (doing this alignment) found that his new aftermarket aluminum top clamp wasn't machined properly and sent it back.
But the idea is simple - just do what measurements are required to find out if the fork tubes are parallel and both in the same plane.
That's all! Not a big deal really.
But where both Excuvator and I had problems was getting the tubes parallel by blocking (or whatever means) with the idea of the lower tree relaxing into the new 'set'.
What did, was heating the triple tree with a propane torch (while under tension to be parallel) - and that relaxed it and allowed it to take the proper set.
Wanted: Dead, smashed, crashed or trashed gauges
BMW GAUGE REPAIRS - TACH*SPEEDO*CLOCK*VOLT METER *PODs & LIGHT BOARD*