If you are talking about a bike with gears .. like an 18 speed or something , thats the wrong tool .. the tool you need looks similar , but nothing sticks up from the end.
it is a 12 point splined socket .. looks like a torx wrench , with twice as many teeth .. again similar to the other tool , with a hole going through for the axle
I think the 2 small dimples you are talking about are for the sprag clutch .. don,t try to take that apart
I'd go to the nearest bike shop. They have the right tools, and they may or may not charge you. You don't have to shop tools, and pay for something you'll probably only use once.
I find I get a lot of freebies from my bike shop, but I don't grumble about the bills when I get them, and they know its a motor bike.