Endless Oil Leaks

Hi folks..

I have a 1975 Z1 900 with a 1390cc motor, built with mostly APE parts. Using a 1982 KZ1000 J head.

It's a nice bike to ride, but I am forever chasing oil leaks. Piping an extra breather out of the oil filler cap helped, but I can't seem to stop the cylinder base from leaking. I'm using an 80 thou aluminum base spacer to get the deck height I need, with stock paper gaskets on either side. Used a bit of ThreeBond 1211 silicone. Seemed like it was OK until I did a re-and-re on the head. Now it's leaking significantly.

Weird. The first advice I received (from APE) was to install the aluminum base spacer without paper gaskets, just using some copper sealant. That leaked, so now I've tried paper gaskets on either side.

It doesn't leak much if I idle around, but throttle up even a little and it gets messy. Don't think I'm building unusual crankcase pressure- my catch bottle isn't collecting much.

Why does this area want to leak so bad?! Very frustrating, I must say.

Any thoughts would be appreciated - -

Mark

"SkidZmark"

You could try a top end oiler kit.

You could try remote oil line to the head and bypass the stock oil passage though the case and up the outer stud passage / cylinder to head.

Just get the pressurized oil out of that area.

Anytime you pull the head off these you will most likely upset the base gasket and then when you put the head back on it will leak. You need to be VERY CAREFULL when removing the head or just replace the base gasket every time you take the head off.

Thanks for the input.

Have to admit I hate replacing base gaskets. Mostly because I have so much trouble sliding the barrels back on to the pistons. Snapped enough rings I have a guy at the shop do it now.

Even with the pistons already in the bores, then tapping them down to align with wrist pin holes. Can't seem to do it- they always spring free before I can get them hooked up. The guy at the nearby shop is able to do it, but I think he's sick of seeing me.

Mark

SkidZmark wrote: Hi folks..

Used a bit of ThreeBond 1211 silicone.


Mark,
Here I go again,
There is NO place on any bike engine where you can use silicone,EVER, unless it's an emergency.

So it sounds like your silicone failed,
OR
If you are building that much pressure in your cases it sounds like a broken ring or two.

PS If you remove the 2 paper gaskets and just use spray copper coat on the spacer you do know you are raising your deck height (and compression) by the thickness of 2 compressed paper gaskets right?

Good luck

Mike

What is your engine breather system. You might be running way too much pressure from those big pistons stirring up all that air in the cases.

Re: crankcase breathing. I use the stock bell housing breather, on the flat part of the block beneath the carbs. I tried a cool looking APE low-rise breather cover, but got oil spray. Seems the baffles inside the bell housing are necessary.

At any rate, the motor continued to push oil out every crack it had until I added an extra breather from the oil filler cap- I run a tube from a hole in the filler cap to a catch bottle. The leaks settled a bit, but I wonder if I've adequately dealt with the crankcase pressure issue. If I haven't, I'm not sure what else there is to do. Any ideas..?

Re: use of silicone. I thought it would provide the best base gasket seal. I'm hearing enough negative reviews on use of silicone to simply stop using it. Next assembly I'll use copper spray. Just hope it has the same sealing ability. Also, when adding paper gaskets to the base assembly, I used a narrower aluminum spacer, to duplicate proper deck height.

The bike runs well. If it would stop leaking I'd be a happy guy.

Really appreciating the advice and input..

Mark Tonner

Have you done a Leak Down Test, to see if the rings are indeed sealing properly?

SkidZmark wrote: Re: crankcase breathing. I use the stock bell housing breather, on the flat part of the block beneath the carbs. I tried a cool looking APE low-rise breather cover, but got oil spray. Seems the baffles inside the bell housing are necessary.

At any rate, the motor continued to push oil out every crack it had until I added an extra breather from the oil filler cap- I run a tube from a hole in the filler cap to a catch bottle. The leaks settled a bit, but I wonder if I've adequately dealt with the crankcase pressure issue. If I haven't, I'm not sure what else there is to do. Any ideas..?

Re: use of silicone. I thought it would provide the best base gasket seal. I'm hearing enough negative reviews on use of silicone to simply stop using it. Next assembly I'll use copper spray. Just hope it has the same sealing ability. Also, when adding paper gaskets to the base assembly, I used a narrower aluminum spacer, to duplicate proper deck height.

The bike runs well. If it would stop leaking I'd be a happy guy.

Really appreciating the advice and input..

Mark Tonner

I think you need to vent the valve cover, did you remove the two rubber pipes inside the derby breather and leave the plate? Years ago a friend built a big motor and used the exhaust system flow to help vent the crankcase. You need to try and look up some old Kawa drag bikes to see how it was done way back when. That engine only has 4-6 lbs of oil pressure because of the roller crankshaft....

Skidz as Motorhead says it might be blowing by the piston rings, a friend has had this on his GSX. Which made for alot of head scrathing until we figuered it out :S Try a compression test. If thats not the answer APE`s Jay is a member here and should be able to point you in wright direction

First off your going to have oil leaks running that big motor, unless you dry block (external oil feed line) it. someone posted a link on how to sleeve the oil galleys to stop the oil leak. Mine leaks oil also. I turned both of my cam cover emmission ports into crankcase vents, by just removing stoc reed valves drlling two holes in the inside and filled it with steel wool to work as a bafffle works great so far. You will have allot higher crankcase pressures running them big pistons. But you could still do a compression test if you thought there is a problem.

I'm sure everyone already thought of this, but are you running 4 quarts or 3.5 quarts of oil?

It's a stupid question, but it might be that the additional crankcase pressure combined with too much oil is making these leans an inevitability. The fact that you're blowing out of the breather is the only reason I'm asking - that's the first symptom of too much oil.