Re: Gas tank
Yes, I experienced cracks at the base of 3 of the studs because they were overtightened. However, there was a reason that I overtightened them. I thought it would be a good idea to put a big piece of rubber underneath the tank to keep it secure. Well since there was more space, I had to tighten it more and the rubber acted as a spring, putting extra elastic pressure on the studs. To top that off, having the rubber there probably transferred vibration to the studs. Not good!
After doing a bunch of crap to try and fix the leaks, I ended up getting a replacement from Pirate Cycles. Now, instead of rubber, I simply have a piece of double-sided Gorilla tape. No leaks since!
By the way, throw out your chinese petcock immediately. It's pure junk because not only is it prone to leaking, but it actually restricts the flow of the fuel! Open it up and you'll see what I mean.