Prior to 2009 the factory didn't 'Glue' the bevelbox to the swingarm with silastic. The actual seal of the front boot relies on the rectangular clamping plate, (Retained by two small self tapping screws.) crushing the nitrile of the boot between the plate and swingarm to effect a seal that prevents oil escaping into the swingarm.
The thing is it doesn't do it particularly effectively! This means it is quite common for early bikes toget a slight misting around the join, oily deposits in the swingarm and, if the leak is bad, a drip from the rearmost hose clip on the swingarm.
While usually primarily cosmetic, the bevelbox has a breather so it isn't pressurised to 'Force' oil out, it was considered unsightly and worrying by some so in 2009 they started applying great gobs of silastic to the jointing surface before bolting on the bevelbox. This certainly cured the weeps but also makes it an absolute bear of a job to get the bevelbox separated from the swingarm!
What I have done on 'Weepers' is to remove the plate that holds the boot in place and cleaned both boot and mating surface in the bevelbox case carefully with metho or some such volatile and then used a thin smear of threebond between the lip of the boot and the case before re-installing the plate and bolting the bevelbox back onto the swingarm. While it may not prevent weepage as effectively as the litre of silastic used by the factory it does help and doesn't make getting the box off the arm again a completely horrible job!
As mentioned above it could also, possibly, be the pinion seal having let go or the pinion nut having come loose but if the seal goes there is usually lots of oil around the pinion and if the nut has loosened the box will howl like a banshee on the over-run.
I reckon it's just a weepy boot.
Pete
