1998 Yamaha Grizzly 600 oil leak June 14, 2016, 11:31:32 pm Friend of mine referred someone to me with an issue. They agreed to fix a friends quad and got in WAY too deep. The "little oil leak" around the head turned out to be stripped out holes in the cylinder. The valve cover is held down on the timing chain side by 4 very long socket head cap screws. Two of the threads were stripped out, two of the heads were stripped out.They brought it to me so I drilled the two stripped out heads out and removed the head and cylinder. The cylinder will need a helicoil and new bolts will have to be sourced. Considering the semi-rare nature of the bolts, the replacements will either have to be in a bolts "grab-bag" off Ebay or direct ordered from Yamaha. I'll snap some pictures when I get a chance.