My 2010 Tenere has just turned 42,000 miles, it's been heavily abused off road, been to Nordkapp in 2012, (5000 mile trip taking in most of Scandinavia), loaded with camping gear. Last year I rode from Ireland to Italy with two other XT660Zs and an XT660R and completed the Stella Alpina off road event, well over 9000 feet in altitude. All four bikes performed faultlessly and 3 of them had over 30,000 miles on the clock. Engine and gearbox still trouble free. Only problems have been a dry head bearing which was replaced by Yamaha and a derailed chain that caused damage to the rear suspension arm - this could have been prevented by myself being more diligent with adjusting the chain. With doing so much off road work I tend to run with the chain a bit looser than Yamaha recommend. A chain guide has since been fitted. I fastidiously change oil and filters at the recommended mileage and often do an extra oil change between the recommended ones. My experience of 660s is that they are extremely reliable and rugged engines. Kev's fuel mod and O2 mod really help to get the best out of them too.

I wouldn't worry too much, especially if you're buying new.

:-)

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