Motorcycle Safety & Driveability: YZF 600 rattle, yamaha yzf 600, cam chains

Question
Hi Nigel, I recently purchased a 96 Yamaha YZF 600 (known as a thunder cat in some parts of the world). It develops a rattle over 8000rpm (though performance is not affected). The bike has previously been dropped on the rhs and I thought that the bodywork may be noisey as engine vibration increase with rpm. It has 90 000klm(54000mls) on the clock and I have been assured that all services have been performed. In my experience cam chains and valve gear are noisy at low rpm and the noise is reduced as the rpm increases. Is there any problems with these engines at these sorts of miles?  With out riding the bike I know it is hard to judge what is wrong but an opinion would be great. Thanks  

Answer
The Thundercat does have a few problems which could be the noise you are hearing.  The cam Chain tensioner is a well known fault at that mileage and may be the thing that is rattling.  Also the little ends are a little suspect.  In a nutshell, with that mileage a bike to be avoided, Sorry

Regards

Nigel