When rebuilding any four-stroke engine replacement of the valves is a sensible precaution. The exhaust Valve
has a particularly hard life and can go brittle with the high temperatures leading to a Valve
stem failure! This is a disaster for the engine allowing the Valve
head and piston to destroy each other!
You will need to fit these new Valve
-Guides at the same time to avoid oil creeping down the Valve
stems and causing the engine to smoke.
Order new Valve stem seals to go with these. Don't forget to order your cylinder head gasket. Use the same sealant as the factory professionals: 08C70K0234M.