Opinions on trustworthiness/safety please!

Hi. Please let me know what you think about this. I have a dear friend who I have been spending some time with, talking, hanging out. We celebrated his b'day last month and will celebrate mine this month. He calls, I call. It is nice and so far platonic, and it is all good in that regard.

I help him with stuff when I can and he recently offered to help me with a car repair, which seemed to go okay as far as I could tell. lol

He also offered to help install a door knob. This is where it gets sticky. My standards are apparently higher than his when it comes to finish work. I was really disappointed that the screws were not in straight. He also seemed to invent a reason to install one of the parts lower than it appeared to be necessary. Unfortunately, I let him look at a fluorescent light bulb that had burned out and he broke one of the arms that the light bulb is supposed to rest on. That was strike two.

The problem is that, with my car, I thought it had apparently been done correctly (I was a little concerned that some dirt may have been introduced into the part he was working on though, and I overlooked that at the time). He seemed to have all the right tools and knowledge for that and know what he was doing.. After he was done with the car, I thought I may have previously underestimated him as possibly being a bit of bull in a china shop or someone who may not have been as careful as I would have been in the area of perfection when performing skilled work. So, I let him work on the doorknob and then the lightbulb, both of which were disappointing as far as end result.

So, now the issue at hand: He has been bugging me to go out for a ride on his motorcycle and insists he is very safe, but now I don't trust his standards for safety as his standards for quality work were disappointing. It is all about determining areas where you mesh, right?

I hate to discover 10 miles from home that my doubts about his level of care with workmanship on areas that are important to me (my home and car) are equal to my doubts about his safety as a motorcycle driver (my life and safety).

Do you think there can be correlation, or should I just trust my instincts and explain why I have been hesitant about getting on the bike. I am not sure I trust him completely. If this were another situation--getting too involved in a relationship, for example--I would know just what to do. This one is a little trickier (I can't necessarily make the connection between poor quality workmanship and safe driving). I have no interest in getting on a bike with someone who is as careless with my safety as he seems to have been with the repairs he did on my home, the home repairs being relatively minor in comparison.

What do you think? Should I just agree to a short ride or explain why I question whether we are on the same page as far as his concern for my well being?

Thanks for your thoughts.