Hay Jim !
my 2012 Ninja 250R has valve shims in it Right? and the manual says I don't have to check them till 7000 miles.... BUT it is cold blooded and doesn't want to run good till it's warmed up like you mentioned.... could the valves to too tight?
you got me wondering now ! I've NEVER heard a tappit click in that bike yet..
and it's got over 6k miles on it and as far as I know no one has ever checked the valve clearance....
....I've never heard that description given for tight valves before... see your teaching an Old dog new tricks !!!
...in my youth you checked the valves everytime you changed the oil... without fail.... or you'd regret it !
these new fangled contraptions are definitely different ! LOL
....
Bob....