I have an ESR 310 prox kit on my bike. This past weekend the rod bearing let go and tore up the whole engine. I thought it went lean at first but then took it apart and saw the destruction of bearing bits come up from the bottom end and chew up everything (piston,head,cylinder). Anyway long story short I want to get a new OEM crank but there are only long rods available. On the ESR website they say that with a long rod you have to use a spacer plate, but I dont want to, I was wondering why I couldn't use the long rod crank with an 87-89 piston and no spacer? The only thing I could think of would be if the big bore piston were only available in 86 style? Also, the new bore will put me at the max of 73.5mm for the 310 kit. How bad is that? Thank!! and sorry for the long post P.S. I posted this in C-Leigh's forum but I figured more ppl may see this here.. Thanks again!!!!