Originally Posted by HDF Tech

For the most part the evo's had some problems with the cylinder base gaskets weeping or even breaking on ocasion. They were like a thin paper gasket as compared to the "O" rings of the twin cams. The rocker box gaskets were a weak point also, other than that , they were great motors.Clean out the lifter screen which is under the big screw head over the oil pump. They tend to accumulate sludge in there which restricts oil to the upper end.