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How I checked my S3 check valves
http://www.kawi2strokes.com/forum/viewtopic.php?f=13&t=2939		 Page 1 of 2
Author:  rotortech [ Thu Apr 05, 2012 1:52 pm ]
Post subject:  How I checked my S3 check valves
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.
Image

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

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.
Author:  BarryB [ Thu Apr 05, 2012 2:10 pm ]
Post subject:  Re: How I checked my S3 check valves
Good post. I bought a MityVac while ago - great little tool at a very reasonable cost.
Author:  rotortech [ Thu Apr 05, 2012 3:38 pm ]
Post subject:  Re: How I checked my S3 check valves
Thanks Barry. I posted because I have no idea how or if everyone else is verifying their check valves.
Author:  mraxl [ Thu Apr 05, 2012 3:39 pm ]
Post subject:  Re: How I checked my S3 check valves
You did good!
http://3cyl.com/mraxl/TomsTips/oil_lines.htm
Author:  rotortech [ Thu Apr 05, 2012 5:52 pm ]
Post subject:  Re: How I checked my S3 check valves
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?
Author:  Jim [ Thu Apr 05, 2012 6:09 pm ]
Post subject:  Re: How I checked my S3 check valves
rotortech wrote:
mraxl - that was the article that I read with the nice pressure test fixture.

Did you scroll down?
Author:  rotortech [ Fri Apr 06, 2012 5:29 am ]
Post subject:  Re: How I checked my S3 check valves
Jim wrote:
rotortech wrote:
mraxl - that was the article that I read with the nice pressure test fixture.

Did you scroll down?

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

Here is a picture of what I am talking about:
Image

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.
Author:  Jim [ Fri Apr 06, 2012 8:30 am ]
Post subject:  Re: How I checked my S3 check valves
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.
Author:  rotortech [ Fri Apr 06, 2012 9:14 am ]
Post subject:  Re: How I checked my S3 check valves
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.
Author:  Jim [ Fri Apr 06, 2012 9:44 am ]
Post subject:  Re: How I checked my S3 check valves
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. :lol:
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