Mate, I'd start with an oil change using semi-synthetic oil (Motul 5100 is good) and adjust and lube your chain.
Other simple things to check include the adjustment (positioning) of the shift lever, make sure the shift lever is appropriately lubed and correctly tightened.
How many km's on the engine and 'box? Oh, and if you end up ditching the motor look up Slow and Wobbly and offer him a belated birthday present
