Today I went to local bike repair shop and asked a mechanic to check front suspension knock.
Before going there I pushed handle bar down to check knock(there was no knock), jacked bike and pulled wheel forward/pushed back (no free play).
Mechanic pushed handlebar down and we heard squeaking noise. Guy said, forks needed rebuilding. He said forks were empty.
I pointed at draining bolt and asked if I should fill oil first. He said it was not a draining bolt. So he was either too stupid to know about drain bolts or lied to me to prevent me from filling oil and eliminating the knocking problem w/o paying him $150 for forks rebuild.
Another time I went to the repair shop to diagnose KZ1000 motor rattle. Shop owner did find location of knock but diagnosed it wrong. (it was lose bolts of starter clutch, nothing serious)

 

Harley doesn't use drain bolts anymore. Have to pull the forks and turn them upside down. At least with dynas the '96 evo has them, the 09 tc does not.

I'm also going to point out the irony of someone who gets mad at a mechanic for getting something wrong or taking too long to finish the job... Yet that same someone won't pick up a tool themselves.

 

My bike has drain bolts and parts diagram shows them. Maybe police bikes have them. I go to mechanics for diagnosing problems sometimes, but I fix everything myself.(including jacking up a house with 20-ton hydraulic jacks.)