Well I did some testing last night, I put a guage on the line from the main tank to the spill tank and the presure didnt build until the sled got warm. The psi built starting at 2-4 and kept rising intil it was at 11 and stayed there, but the sled was super warm. Should that cap be bleading fluid by at 2-4 psi? or even 6-8 psi?? I put a polaris edge 800 cap on there and the guage quit moving, it stayed at 0, it didnt even move till the sled was hot. So is that a bad cap??? If I had a bad gasket it would have been a rise in psi from the beginning, instant?? I think I just over heated the sled by doing too many pulles in a row and the cap was not sealing. I would be checking your caps to see what psi they open. What psi is the yamaha cap? The polaris cap says 13 lbs on it.