I am trying to figure out the problem on a 1999 polaris 400 sport. HPD head, .080 over-bore. It idles great when cold, after first 5minutes burns through half the coolant, at idle there is alittle foam in the coolant, not much. compression is 140 cold. when the engine is cold it will hold the coolant with no leaks. The head and cylinder are flat and it has a new head gasket. What could be the problem???
Thanks Jason

 

if its not a stock gasket then it could be that. i put a cometic in and it blew in like the first hour

 

if your burning that much it would be pretty easy to tell by smoke and smell.

 

it is definalty burning the coolant there is lots of whie smoke. The o-rings for the hpd head are what was put in ti and it is sealed. any ideas on what else would cause this thing to leak??
thanks, Jason