As a counterpoint to the 'how much is my time worth' I would contend that my free time is worth $0/hr. Why? Because this is a hobby where I'm not supposed to make money. If I wasn't doing this, I'd be doing something else that cost money. I could fish, hunt, m'cycle, golf, etc., etc., all of which cost money every time I do them (some of them more than others).
To carry that a step farther, let's say I got a part time job to pay for the drivetrain. Let's say I get paid $10/hr. First off, I wouldn't have as much free time (which, as you will recall, is worth $50/hr). So, by working, I'm losing $40/hr. Yes, I'm being facetious, but it was fun.
Anyway, I've thought about the PT job to pay for toys/hobbies and always decided that I'd rather wait, dicker, barter, etc. But, to each his/her own.