DON'T put synthetic oil in the trany. I speak from experience...it will DESTROY all the seals, even the bastard one behind the primary gear. I use Bel Ray gear saver oil, expensive yes, worth it yes. Don't use cheap oil in your monster they are expensive to fix, much more expensive than the oil, trust me. I am a machinist and have drilled a blind hole in the oil plug (on the lathe)and inserted a .100" x .375" magnet that pulls 2.5 lbs to pick up any debris that might recirculate through your trany. I use Bel Ray H1R full synthetic mixing oil at 40:1 with excellent results. There is a small screw behind near the end of the brake lever to check the level of trany oil. Just add oil until it runs out from this hole. It is there just for that.

87 QZ
87 QS

 

The reason I use Castrol 10w30 is because I change my oil after every couple of rides anyway. With all the clutch particles floating around in the cases mingling with my bearings, I dump mine and replace it. I've used expensives oils but they get contaminated too and wind up lookin' like day old coffee. I don't want any foreign material floating around my bearings if I can help it. The magnet thing is a good idea, I will do that. Stormnorm and some independent lab reports I've read have me warned off synthetics, so far so good. REAL good.