Kawi2strokes.com Forum

While I am awaiting some other bits and pieces I decided to verify the function of the check valves on the oil injection lines.

For reference the bike is a 1974 S3 and the lines appear to be originals.

I saw the beautiful pressure checking block in the How To section on Check Valves. I don't have enough of a machine shop here to whip one of those out so I used some hose and a vacuum pump with a gauge to do the trick.

Here is the set up. I used one of the banjo bolts, two orings, a piece of 5/16 hose and a clamp.


Here is a close up of the way I attached the hose to the banjo bolt. Crude, yes?


When I attached the hose I grabbed the hose in my fist and pushed down on the bolt with my thumb while tightening the clamp. Then I pumped the vacuum pump a little. I heard some air gasping and held the banjo bolt to my ear to verify that it was leaking there. On the second try - no air leak. The gauge showed 5 inHg and it was steady with no leakdown. So I tested the other two check valves and they are all the same - 5 inHg. That is equivalent to 2.5 psig. I feel confident with that number and will go ahead and use them as is. I was paranoid about oil control and did not want to risk taking these apart.

I wanted to share this with others who might be wondering about their check valves. Even though my bike is the S3 you could use this set up for any model to test cracking pressure and leakdown on check valves.

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Rotortech
Indianapolis
1974 S3

Good post. I bought a MityVac while ago - great little tool at a very reasonable cost.

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This is true. Where I grew up the hills were so steep and long, when your ball rolled down the hill you just said "screw it"...

Thanks Barry. I posted because I have no idea how or if everyone else is verifying their check valves.

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Rotortech
Indianapolis
1974 S3

You did good!
http://3cyl.com/mraxl/TomsTips/oil_lines.htm

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Answers are here: http://kawatriple.com/

mraxl - that was the article that I read with the nice pressure test fixture.

I have a question. The bottom of the banjo bolts has some sort of fitting in it. It is not a plug because some air can pass through. Does any one know what is going on there?

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Rotortech
Indianapolis
1974 S3

Did you scroll down?

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If it surges, that's normal, upshift.

Jim - yes, I scrolled down and up and everywhere. No mention of the bolt.

Here is a picture of what I am talking about:


After some consideration (probably too much consideration) I have decided that it is a pressed in brass plug. It is not air-tight, but prevents most of the oil from going straight down instead radially as intended.

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Rotortech
Indianapolis
1974 S3

As I remember, the "straight down" oil goes to the crankshaft, and the "out the side" oil goes to an intake port. The restrictor in the port and the restrictor in the end of the bolt control how much oil goes each way.

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If it surges, that's normal, upshift.

On this engine there is a just a blind hole that is tapped for the banjo bolt threads. There is only one drilled hole intersecting each banjo bolt hole. I think the plug in the bottom of the bolt is not essential in the S3.

Like you, I thought that some oil was injected directly into the crank bearings but that isn't true for the S3 - per the manual and what I can see on my engine.

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Rotortech
Indianapolis
1974 S3

Yes, you're right. The manual says the oil is mixed with the incoming fuel. The parts manuals show that the same bolt is used in the S and H series engines, 92060-010-79. By the time I build an S bike, I might know something about it.

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If it surges, that's normal, upshift.