UPDATING……….I said I'd report back. I dropped the ATF (Valvoline Dex/Merc) that was in the primary after 4900 miles, and the drain plug looked real good, there was a small amount of that grey paste looking stuff on the magnet, I'd say no more than half a BB if you can picture it rolled into a ball. That's seems to be reasonable based on what I've seen in the past. No other odd shards or artifacts. Based on this I'd say there was no excess wear going on. FWIW my bike is a 2000 RK which has the old style compensator which seems to be the robust version.
The fluid that came was definitely not clean and clear, but it wasn't burned and black either. It was more like a semi opaque dark maroon color. Nothing much to see there, which is good.
Throughout the OCI the clutch feel never change a bit, the engagement was silky smooth the whole time, finding neutral never a problem, and no bang going into 1st gear hot or cold. Sometimes barley a click, sometimes maybe a slight snap, but never a bang. I think that's about as good as this bike will get. Shockproof Heavy does a good job to keep the general shift action good.
For this OCI I filled with Mobil 1 Syn ATF. After a few hundred miles I can say it feels about the same, which is to say really good. Maybe a tiny bit better going into first, not sure, it may be the placebo effect. Seems the same as far as clutch feel goes. I went with the Mobil 1 mainly because its a synthetic and I ride all year round which means from like 32 to well over 100 (aka free kin hot), and I wanted something that withstands heat well. I also use the same fluid for my suspension front and rear, similar reason; I wanted a synthetic to minimize the viscosity variation from hot to cold to try to keep the suspension feel consistent. Using the same ATF for everything appeals to me from a simplicity point of view.
Anyway, I find the ATF works good, at least for my bike. I feel pretty comfortable with it. I could get talked into going back to 15w40 too, it's just a couple ticks off on the feel side of things. Personal preference thing.
Tell ya one thing…….I hate that old style primary drain bolt (no head, no taper, no o-ring), you could screw that thing right through the cover if you wanted and never be sure you get a great seal. I had to break down and pull it the other night, which meant dropping the ATF obviously, just so I could re-wrap it with teflon tape to solve this blasted weep. I thought 4 wraps would be plenty………nope. Try like a least 7, going in the correct direction only, nice and even the entire length of the thread, and make sure the bolts is 100% oil free before you apply the tape. Finally got it. Those oil weeps drive me absolutely batsh** crazy.