If you have clearance you will have noise, it just might be that some motors/ bikes amplify it more.
Phil Irving, who designed the Vincent motors and had a hand in the Velo pushrod singles admitted to being perplexed as to why the AMC pushrod motors were much quieter than the competition - he had examined them closely and couldn't find any reason why it should be so.
So we are in good company!
Some folks have tried a bit sound deadening, Hitchcocks have the gear, and stuck to the underside of the tank, and sometimes every other available spot, claim to notice a difference.
Choice and quality if oil can make a difference too.
And perhaps it was designed in as a safety feature, to alert us that adjustment is needed!
Could be worse, my nearest Lawnmower guy shims up bevel desmo Ducati's when mower work is slow midwinter. He usually has a waiting list and is thinking of putting up the price, $ 3,400- cash up front doesn't seem to deter his customers. Actually a ex race mechanic who does the mowers as a side line on his organic farm, but -----!