I think one of the problems with our bikes is the fact that there is so much fuel BELOW the petcock. The petcock is like in the middle of the tank. I guess it is good to have a deep reserve but how do you get the fuel that is below the petcock back up to it to burn? This problem is nicely solved with the Clarke and IMS tanks and the petcock is at the bottom of the tank where it belongs. I wonder if these companies paid Yamaha to put the stock petcock where it is. I am pretty sure that if the stock petcock was on the lower left front corner of the stock tank like it should be I would never have found it necessary to buy the Clarke.