1998 evo leaking from front lifter cover/pushrods?

Question

bike ran fine 30,000 miles on it changed air filter and plugs , i was riding down the road and noticed oil spraying out of front lifter cover , i lost about a quart, i have not done no work to bike yet im wanting to know if any one has some good ideas what would cause that to happen besides the obvious,like a bad lifter cover gasket , thankls

Answer 1

the crancase vent tubes are located on carb breather houseing and bolt into boxes you have restricted the vent tubes causeing a pressure build up into rocker box causeing leak take a good look at your new breather installition assumeing thats all you have change

Answer 2

It may just be "one of those things that just happens".

Overfilling the oil is somewhat easy to do.

Thats jacks internal pressure Sky High and will find any marginal sealing joint.

They'll also "temporarily overfill themselves".

Oil check valve lets tank drain back into engine sump>>fills bottom end w/oil.

That displaces a Bunch of volume.,,,again raising crankcase pressure.

If the Cover bolts get loose,,,,it'll move around .

"Move Around" is NOT like it may sound----It's Obviously Not hopping up & down on the head.

But they will shift and squirm a Tiny bit.

That also accounts for the Tubes leaking---they're involved also when cover shifts.

One other thing---and if I have not earned my Thumbs Down for this answer yet,,,,This Always Does.

The Breather Valves in the rocker boxes(aka Umbrella Valves) are c**p.

They work fine when and while they work.

When they fail the engine is allowed to INHALE Air.

Then when Pistons go Down,,they compress that air in the Crankcase,

How MUCH Pressure?

Go stick your finger over the sparkplug hole and Crank it.

That Only ONE cylider.

The Crankcase does Not have the Compresion Ratio of the Combustion Chamber,,,

But it DOES get the Air Volume Displacement of BOTH pistons going Up & Down.

It's a BUNCH of air volume(Full Engine Displacement) and pressure,,,forced to Exit & vent thru a hole smaller than a pencil.

Normally the Breather Valve acts like a 1-Way Check Valve.

Pushes air OUT,,,but cannot suck it back IN.

So,With NO  Inhaled Air to Compress,,,

Crankcase pressure remains Very Low----ZERO.

But when the Valve Leaks,,,Your Crankcase becomes an Air Compressor.

It Fills the case with Air when pistons go UP,,

And Compresses it when they  go down.

Suction /Vacuum when pistons Rise dont bother gaskets at all.

Pressure when they go Down is seen at every gasket/seal/o'ring.

It's GONNA find any  Weak Link,,,,and Leak.

It also make them occasinally blow oil outa the breather into Air Filter.

'Cuz of the sheer VOLUME and Pressure forced thru the Breather.

Anyway,,,,any sorta top end leak on those motors deserves attention to the breather umbrella valves.

It's just a little tiny rubber button.

10 Years in it's operating environment makes it a suspect also.

The Breather May NOT be the Direct Cause---but there's a Good chance it's surely a contributor.

Good Luck,,,

Odds are  'bout ZERO you have any serious problem.

(Except for Serious Mess :)

Answer 3

get the blue silicone push rod tube seals from an independent parts store or catalog, their a whole lot better than stock ones.

might be a good time to switch to adjustable push rods(cheap ones are$84.95 from jirehcycles) you can just cut & remove your stock push rods with bolt cutters & wont have to remove or lift your rocker boxes.

Answer 4

When you changed the air filter, did you make sure the breather hose was properly attached, or did it get kinked or clogged in the process?  The breather that TMX was talking about is used to relieve the pressure that builds up inside the crankcase, and it feeds that into the breather where the engine can use it.  If the pressure cannot escape the cases and heads, then it goes for the next weakest point.

There is oil that drains down the pushrod tubes and helps lubricate the lifters, then the gears, cams, etc. so if there is a clog in that area, then it cannot continue to drain into the bottom of the crankcase, and will overflow.

Answer 5

Think you answered your own question.  Time to replace the gasket.  At 30k on an Evo is pretty good, w/o a rebuild. My '87 Heritage Softtail didn't do that well!

Answer 6

try re-torquing first,if it still leaks,replace gaskets