Hi guys

I have a Yamaha XT660Z Tenere 2013 with 19.000 km on it. I have changed the oil for every 5.000 km with Motul 15/50.
The bike today started developing a knocking sound from the engine. It only appears when the clutch grip is released. When I pull the clutch the sound disappears and the bike runs like normal. It sounds like one of the bolts from the clutch has backed off and is hitting the clutch housing now and then!

Any suggestions or is it the main bearings that are ready for change?

Cheers

mhoey