Upon installing one, let's say... from all the way in... several turns before it's even close to anyone's finger tight, how long making the noise at totally loose then would you guess it would take to eat the teeth off one of the gears?Mine is quiet both ways. When I did the adjustment with the bike off it didn't make the whirring sound so I may have had it slightly too tight. Guess I have superman fingers
... mine might be tight as well.. and that might be that grainy noise we heard. I read this you wrote today, and today when riding... i heard the same thing... the 'whistle' sound... whir... sounded like a brand new Z1 900 with its huge fan. I am only playing with one front cylinder though too.