My '99 XT600E has developed a disturbing trait, which I'm wondering if anyone else has experienced. The plastic bung in the top of the gearbox, under the starter motor, which plugs the hole where the clutch shaft used to be, has started to pop out at inopportune moments. The first time was at speed and the engine pumped out a large quantity of very hot oil onto my left foot (and rear tyre!). Just recently it has happened again while I was off the bike closing a gate, with only a little oil loss.
The hole itself is on the low pressure side of the oil system (I think), so I'm not sure why it is popping out. However with the bung out, the engine will quite happily pump oil out of the hole. I'm not sure if this is relevant, but my bike has a CoolBlok oil cooler and thermostat fitted, from Wunderlich in Germany.
I've tried to replace the bung using various adhesives, but the high temperature and plastic-metal interface aren't ideal for this. From an engineering point of view the optimal solution would be to tap the hole and get a threaded cap made up to screw into it. But this would involve me removing the engine, and finding a precision engineering workshop, which would probably cost a lot of money as well.
So, has anyone else experienced this as well? Is there a simple solution to this problem?