You'll start to notice the play in the cush drive long before it fails.
Mine was so loose that when I started to slip the clutch, if I looked down and back at the sprocket I could see the sideways movement of about 10mm at the rear.
The standard bearing has a seal in only one side. So it fills with dust and crud every time you ride/wash it.
The bearings I got from Suzuki as replacements were off the shelf SKS bearings with 2 seals. I repacked them with a mixture of Moly grease, Nulon grease and added Graphite. My own concoction that is aimed at being both a grease and an anti seize.
I think the standard bearing gave out at around the 18000km mark. Bear in mind that I do around 50/50 trail/tar commuting. After I fitted the new bearing the bike has been used for trips and trail riding only. No commuting.
Pulling the DR up is an interesting exercise. I used the RMZ front end complete, and the brake disc is smaller - 265mm - so brake force decreases. In the dirt I can still lock it up, but tyre selection is crucial to getting it to stop.
At the Tallanganda ride I used the Mitas E09 front and rear, and the biggest thing I noticed was the front will not hook up on single track. Great on dirt roads, tar roads etc, but forget it on single track. I also had the RMZ rear shock working through a modified DR linkage to the standard DR swingarm. The spring rate was too soft if being pushed hard. "Trail riding" the 5.6 spring was good. But the minute you start pushing harder, like chasing the guys on the 250s and 450s, then you have to have the compression damping up a little harder and it tends to hop in the back end, which in turn affects the way it brakes and steers coming into tight turns.
I did a lot of tyre testing after that because I didn't like the excursions into the trees. I think Steve was right behind me when I hit some greasy clay going hard in third gear. The track dog legged, and when I went to brake it just let go. So I stood it up straight aimed for the gap between the trees and tried to just bull ride it to a stop.
Dunlop 952 front, Mitas Stoneking C02 rear. That combo works best on the dry rocky trails around here. The rear can feel very skatey, but it's predictable. The Mitas will drive and turn, the Dunlop steers and stops really well.
At the moment I'm running a 2006 RMZ front end. The 2007 RMZ front end is off being rebuilt. They are nothing alike as far as fitment issues go. But as far as they work, very similar. The 2006 is a single chamber design, and the 2007 is twin chamber. I prefer working on the single chamber after having both sets stripped down.
A scratched fork leg has chewed up the seal on the brake side of the 2007. So keep an eye on the condition of the lower legs. I knew it was scratched, and I used 2000 grade wet and dry to polish most of it out, but it still chewed out the seal.
Keep me posted and drop me a PM if you want a riding partner over the break.