Ah bugger to late to say the reversed slides (ask me how I know). a good one I found was a a bike that started and ran , sometimes, back fired others and then refuse to start. A broken woodruff key.
A good article I read written by a long time mechanic, customer brings in a gixxer 1100 and says it has a bad vibration at 220k's, tells him to ring in a week, customer ring says it will be ready on monday, customer arrives bike has not moved , "Did you fix the vibration?"
"No reckon just stick to 219k's in the future", customer arcs up and tells hime he's extended his life by a week and a half.
Another time did full rebuild on a multi, comes back in a week with a seized engine , cam cover off and obvious no oil getting to the top, start stripping it down, mechanic notices something blocking a oil gallery, gets it out and it's a small triangular piece of brown glass, customer goes mental, about the same time his best mate rocks in walks over sees the bit of glass on a tissue, " Ah that's probably a bit of that beer bottle you smashed when you put that engine in. Told you to flush it out"
Thinking the vaccum hoses on the petcock not correctly installed?