The EXUP valve needs regular servicing but is quite often neglected , check the price against the Parkers price guide online , the price given is for a standard bike with average mileage , check for cosmetic damage , and if your paying cash , haggle , the valve check is supposed to be done at 24k so it should have been done at least once , how long has the previous owner had it and why is he selling . And don't pay extra for extras .