Hoping for some help, advice here.
After spending a fortune so far on my Z1R restoration, was gutted to get a call from a local guy who is rebuilding the top end of the engine. Unfortunately there are cracks going from a couple of the valve’s across to the spark plug holes, 2 and 3 cylinders . One of them doesn’t look too bad but one looks a bit concerning, 3rd and 5th picture. The bike was running ok before strip down and as some of you have stated on my post for “Wanted head Z1R” that these cracks are not much to worry about? The guy rebuilding it says that” he wouldn’t put it back if we’re his engine “ fearing that the insert could come out below the seat which would be disaster! Thoughts would be grateful, thanks in advance.