Hi, My son and I purchased a 1997 XCR 600. Starts first pull every time but smokes a lot; white smoke even after warm.. Compression is 90, 85 ,90. We checked the oil pump and the return spring is working properly so it is not stuck wide open. We noticed the coolant was on low side in the reservoir when we bought it. Wondering if there is a slight head gasket leak possible causing the lower compression? What would you recommend I try first. New head gaskets?