When you get a mechanic diagnosing the worst possible cause for a problem on the basis of foc-all evidence, he’s really not interested. There are lots of possible reasons for cooling problems.Presumably the bike has a temperature gauge or warning light… was it reading hot?Does the radiator get hot?Had the fan come on?Does the water pump work?Are the radiator passages blocked? (If coolant changes have been neglected you can get a gelatinous, snot-like material forming which can block small pipes.)If you’re not confident in your spannering abilities there’s no shame in taking it to a professional for investigation.. and if he sucks air through his teeth and tells you you need a new engine without eliminating the simple things, take it somewhere else.
I have read on other forums that the Fazer has a rep for a slight rattle in the engine and that it's normally nothing to worry about?