it is a longshot but,the bike has been running fine,done a few trackdays,and a 200mile journey on sunday since last oil change(catrol power 1),the bike suddenly developed a rattle which seems to be coming from top of engine but it is going as normal,it did go away yesterday but was there on startup today and remained all the way to work,seems louder on occasions,it has done 21.000 miles any advice.
Cam chain tensioner costs between £125 and £150 to replace all in. Hours labour plus the unit and vat Mine needed doing but was at higher miles mind...