- Joined
- Jan 22, 2018
- Messages
- 46
went to see Norman White today . While i was there i asked about the perceived problems with the 850 RH4 cylinder head cracking in the roof of the inlet port .He told me that the only times he has come across this problem is when it has had a bad porting job or valve guides have been ham fistedly fitted. although he told me that they do suffer a problem of cracking in the tunnel where the 5/16 studs come up through from the barrel this by the way is both RH 10 and RH4 heads , but deep joy this can be repaired by a laser welding process (dont ask me only repeating and passing on info )