dirty valve

[fasterz]

hey i sent out my z400 head to be ported and the guy called me today and said its done and he said that one of my intake valves had carbon on it, i have 2 intake valves and a dohc motor so it was very strange to have only 1 intake valve with carbon. what could be the cause of this? he said mabey my shims were incorrect but i had just checked them like 2 months before i sent out my motor. what could it be? thanks alot

[hondafox440]

Maybe the timing on that cam was off. Did he mention anything about that exhaust valve? Or does Suzuki have both exhaust on one cam and both intake on one cam?

[fasterz]

both exhaust are on one cam and both intakes are on one cam. he said the one intake cam was normal but the other one has some carbon on it. thats like really werid.