while refreshing the cylinder head on one of our rc390cup bikes we came across one inlet valve cracked so we ordered two valve kits from ktm when these arrived we check them for stem to seat run out to find 5 of the 8 where bent and not useable and contacted ktm uk to be told that they had no problem with there valve quality and to return them for replacement which we are now waiting for has anybody else replaced the valves in there bike and or have checked new valves for straightness ?
inlet valve cracked and new valves bent
To reply to this old post- exact same problems now been found af 2015 CUP engine taken apart 2021 after 30 hours of use ( yes, the bike did stay unused till 2020) , the inlet valves were cracked and outlet valve guides worn as valves were bent. No apparent evidence of valves having hit the piston though, so it also might have been due to the poor quality of the valves themselves (as other components considering one inlet valve shim had broken and 2 valve retainers cracked).
