German Engineering?
![Image](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh_A6UR0IT3YZqjM-8izBOR6FUT93NhQQi1rgMhpqBUmIb7VNstHuq09BWNayKUqHwGM8ek7B-KNThN0vdU_Ues4e-TUYts5aUmieVpi-uUdKilEstm3_50QWjmsL7dc9NIkWRO4sSe-RL8/w640-h342/Valves+before+and+after.jpg)
As mentioned last time, when rebuilding the top end of my R75/6 the replacement heads that I had for it had a few problems. The heads are from an R75/7, so are a straight fit onto my bike because I already have modified the valve gear to a later specification than that originally fitted to my series 6 bike. I have no idea of the mileage these heads have covered, so they were stripped for inspection and cleaned before anything was done with them. I have a small lever type clock gauge which I used to check the valve guides for wear. These at least were well within tolerance, so we had a good start. Next the valves. Both inlet valves looked good and a light lap in with fine paste produced a good seating surface. The exhaust valves were a different story. They appeared to have been seating on a knife edge thin ring around the valve (see the before and after picture below). When running my finger nail across this, the nail actually clicked into a thin groove worn into the seat. Wh