I just noticed the rear cyclinder is leaking oil at from the head gasket. I thought it was running down from somewhere else so I cleaned the engine and ran it agian to comfirm. Oil is seeping out of the gasket. I have never taken the top end apart on an EVO but I have rebuilt many other engines. How is this possible? Does the head on an EVO have oil galleries? Is there anything in the rocker box I should replace while I'm in there? My engine has about 30k on it.

 

Here's what I came across last summer, I had oil coming oil the head gasket seeming to be on the intake side rear front and front back so basicly near the intake, long story short I pulled the front rear cylinder studs and the front rear studs, I fixed them using time-serts. Now this was just my situation yours may be different. Just check your jug studs to make sure the nuts didn't loosen off.

 

i had the same problem out of my front jug, turned out it was a stripped head bolt. heli-coil and back together, now good.

 

There is an oil return from the valve gear back to the crankcase, through the head gasket, on both heads. You'll need a set of gaskets to sort the problem, also check what the other two have suggested. Buy good quality gaskets.

 

Not sure when Harley fixed their stud issues on evo's but mine is an 88 FLH 80 ci. when you pull the heads & barrels off, the studs have a flange on the top threads for the head bolts. What happens in this case is the head bolts torque down & make contact with the flange. it bottoms out & gives you a false reading on your torque wrench. The end result is insufficent clamping force on the head which will lead to head gasket failure.
Harley sent out a service update telling us to unthread the barrel studs & turn them around so the bevel side faces down. I use red loc tite on those threads!
The studs can stretch so you have the option to replace them as well as a precaution!
Keep us posted!
Hatch.

 

Checked the bolts, all were nice and tight the leak is seeping out of the gasket from the back left corner of the rear cylinder (if you were sitting on the bike). I found a picture of the bottom of a head on ebay. It looks like the gallery runs in that area. It looks like I will be pulling the top end apart. Oh my bike recived a new engine in 1998 form Harley. The bike runs great. I was thinking about just tearing down the problem cylinder only to replace the gaskets and leave the front alone. However if the rear cylinder looks bad I will tear down the front as well. Any recomendations on the gaskets?

 

I used the stock harley head gasket and the james coated base gaskets.
You've probably heard a few stories in here about finding oil on the rear head, amazing what the wind will do to a drop of oil.
Is the rear cylinder plug wet by chance?

 

No the plug was dry. What gaskets did you use on the rocker boxes?

 

Get new ones from the dealer.

 

Sounds good. Hopefully this will be a quick and easy repair.