ZX10R puking oil

[sccadsr31]

My engine is a 2004/05 Kawasaki ZX10R, from day one it has always puked out about a pint of oil in a 30 minute session and occasionally a little more. In an effort to stop this I have built a variety of breather cans with all kinds of baffles and drains, very little net positive effect. At ThunderHill last October I hurt 2 engines which is something that has not happened to me in 40+ years of racing. A high compression 14.5:1 puked out over a quart in 10 minutes, twice before I took it out and put in the old reliable stock engine. Old reliable lasted until Sunday morning and gave up before the Sunday race so a DNS there but it did come through for a win on Saturday.

While I have built and rebuilt dozens of the old 1990 platform ZX10's which were all dry sump engines I have only been inside the ZX10R once. The ZX10R is a wet sump and it has a horizontal baffle plate between the pan and the case. This time I spent a long time looking at the internals and examining the crankcase and breathing. The 04/05 has a chamber above the transmission which is sealed and has an external exit about 1/2 dia, the chamber has 2 internal ports both about the size of the tip of my pinky. One port exits behind the clutch flywheel and the other exits about 3/8in from the bottom of the oil pan. So the port behind the flywheel does not do much to relieve crankcase pressure and the other theoretically is under oil all the time and not actually vented to the crankcase.

After thinking about it for a few days I decided to be aggressive and unseal the chamber above the transmission and cut a corner off the sealing plate. Of course there was some risk of the rule of "unintended consequences" but what the heck doing the same thing over was the definition of insanity. Brother Ted and I loaded up and took one of his stock engines as a spare and off we went to Auto Club Speed Way with this "test" as plan A, plan B was change the engine. Running the first session I kept an eye on the red light the entire session every lap every corner every braking zone; no light and at the end not a drop of oil in the breather bottle. The bottle ended the weekend with about a 1/32 -1/64th inch of what looked like a heavy deposit. I'm putting this in the good fix column and figured others may want to try this with their ZX10R's.

Hope this helps some other people as well.

David

Below is a picture of the sealing plate that covers the chamber, the missing corner was selected because it left the baffle in place between the crankcase and the external case exit. That horizontal dark shadow is a scraper designed to strip oil off of the spinning transmission.

[John]

Dave,

Having worn the oil from your engine in the past. I am glad to hear you finally figured out a solution.

Hopefully see you at the track later this year

John

[Northwind]

David,

You are correct with your solution. We had this issue in the early 1990's when we were running the FZ 1000 motors in our DSR. We found that by enlarging the breather opening it slows the breather gases down and allows the gravity to separate the fluids from the gases.

[sccadsr31]

John H,
You have always been a good friend and I felt so bad that day, you were more than angry at me and I deserved it. That was one of the first couple of races with this engine and we had no idea why it was happening and at Laguna Seca it had put out a controllable amount, ThunderHill was a different deal altogether and that is where we found out there was a problem. I added a breather on the cam after that race and started building a series of differently baffled cans.

David

[John]

No worries

I still cant believe that much oil could come out of a motor and it didn't go bang
If you need a hand at the track this year send me a note.