Jase, The open, spring side of the seal faces the clutch, to keep oil in. Some folks would use an extended Gearbox Sleeve Bush to completely enclose the mainshaft, bridging the gap and keeping any gearbox oil moving down the mainshaft and thus depositing it into the chaincase in an effort to keep this area between box and chaincase a little less messy.
Chaincase oil level is better set by draining off, then refilling slowly with the engine running, watching for oil to start flicking past the filler hole as the chain starts to dip into the oil. You just want a steady stream of discrete drops, not a constant waterfall deluge. The oil only needs to come up to the lower few teeth of the chainwheel, not halfway up the clutch! Grease the chainwheel rollers on assembly, it helps anyway to keep them in place as you juggle it back together.
Swarfy.
