how many people have oil leaks before 300 hours

I work on these engines all day. I've found a problem 3 years ago and Kawasaki told me it is a maintenance problem and screwed me out of appox. 2000.00 in repairs because I sold this product and I believe in the engine.
If you buy a new 19 hp vertical engine and run in very dusty condition, it will fail about 400 hours .
The reason is the crankcase breather plate in made of steel and the block is aluminum,the plate will not expand as fast as the block, causing the four 6 m m bolt to loosen.
When this happens it will leak small amounts of oil to be discharged into the cooling fins, which collects dirt and causes major failure of the enigne(head gasket,valve overheating,more oil leaks from seals).
The maufacturer say's to me"it's maintenance problem,not their fault!"
One of their most popular items they sell is the breather gasket, number 2 in the nation?
let's see how many of me are out there. Please respond to this and we'll get some payback some how?