I,ve got a 09 bike with 37k on it and I bought a set of bearings from the Bearingboys for about 25 quid a set, haven't fitted them yet as mine still feel smooth. SKF 6203 2RSH x 4bearings f & r ID 17mm OD 40mm Width 12mm
SKF 6304 2RSH sprocketcarrier bearing ID 20mm OD 52mm Width 15mm