Just make sure you tell him that it might very well cost him his job, and that you are never going to be tossing him more than six-pack money on the best of days.

He is young, probably doesn't know a lot about business, might well think, "Why not?" and then understand "why not" when his boss tells him not to bother coming back to work.

So you weren't even going to tell him---were just going to ask him to risk his job until you didn't need him and tossed him aside? Really?

Seems to me the smart thing to do would be to tell the guy you want to hire him to train you to repair bicycles ... but then you might have to pay him more money and not just for work you need ---

And apparently You aren't good enough at thinking ahead to realize that if you paid him to train you, (which wouldn't be stealing work form his boss or endangering his job) you would eventually not need to pay him or the bike shop, so that paying for training honestly might work out to be the cheapest and most honest option.

You could learn everything you needed, not just how to do the one job you might need at a given time ... and he could keep his day job, because you sure aren't planning to pay him much.

Look, if you Really want to learn to fix bikes ... YouTube? Forget all these lame schemes which involve ruining this kid's career before he even starts. Instead, buy a bunch of crappy, clapped-out bikes of CL ... really nasty tore-up bikes ... or collect them from the side of the road when people are clearing their garages ... and buy your tools, and turn on YouTube and start taking stuff apart and putting it together.

The funniest part of all this is that you want to learn how to fix bikes from a guy who needed three tries to true a wheel.

There is a lot of fail in the world ... but sometimes in concentrates in a single thread.