Re: Second gas tank to crack and leak
Overtightening the fasteners and/or hard mounting the tank is a sure prescription for the failures the OP has. Those little studs or the spot welds on the tank won't take too much torque. Trying to tighten them enough to hold the tank to a steel top tube without some way to cushion the tank and hold it in place is futile.
With road shock and engine vibration that tank is going to slip and move if there isn't something there to help hold it. Something cushy and sticky between the tank and top tube is nearly essential. There have been several good suggestion posted in this thread.
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