Kawi2strokes.com Forum

I have 2 out of the 3 lines that fail the test of "hanging them vertically" filled with oil. I've installed new balls and springs from Jim off off ebay...
I read a number of threads and looked at some really great material on youtube and different threads showing how to disassemble/clean/test ... (Darth's one in particular (** Link below)with the 20x microscopic view of the valve surface). However, I am confused about one thing ...

Before I start messing with 600 grit lapping compound and making up a little lapping tool with a tube+old ball ... I want to check if the general experience of you all who have done this - is that lapping will improve the sealing ... and solve my issue with the leak (knowing I have the new springs/balls in them) ???

I ask because from Darth's analysis in the video, he seemed to say the more lapping and "wider" the sealing surface got, the worse it leaked. He says he cured that by making it more of a "sharp" edge (not sure how) and thus reduced the surface of contact with ball.


Reference: **Link to video on checkvalve thanks to Darth : https://www.youtube.com/watch?v=7dWVe8q ... kP&index=7

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'72 H2 - '72 H2 - '72 H2 - '00 ZRX1100

Darth is right on the money.

.004" is what I found that the valves do not leak with AIR.

Sharp 90° or less is better.

Sandpaper or lapping paste will not clean these up.

cliff

It will be all for naught until you confirm all check valves have a dry air relief pop off value of 4.60 psi relief pressure.

Thanks guys.
The popoff works fine @4.5 or so psi (air only) - so that's all good I believe. The original springs were only giving about 1 psi, if that, so pretty much as if there were no spring LOL.

I am going to take a closer look (magnifier) to see what I am dealing with ... to be continued.

I guess the only way to get back to a sharp edge would be to ream out the hole slightly (2.29 per your drawing if I am reading right or enough to get seat down to sharp edge).

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'72 H2 - '72 H2 - '72 H2 - '00 ZRX1100

I am the one that started all the checking of the check valves and "adjusting" the stock spring, by stretching it, to gain the correct 4.60 psi of air pressure, and your good new springs are right on, 4.50 is right there.

If you make a simple tester fitting for the oil pump end of the lines, you can not only check the pressure, but fill the lines as well. I use one of the longer fitting screws for an oil pump banjo fitting, two sealing washers and a simple 6mm x 1.0 nut, then fit the air hose, or oil hose to it, test away, and fill very slowly, low pressure, just enough to break the ball open off its seat.

Then, to bleed the pump, idle rpm's, cable wheel held wide open with a 10mm boxed end wrench against the cover, and let it flow, look to the right cylinder oil line, when the air pockets are completely run down the line and into the fitting past the valve, done.

I also suggest to have a set of old "beater" spark plugs, used, and cleaned with a propane torch to dry the carbon, and glass bead blasted, into the engine for things like oil pump bleed, other times you don't want to expose a new set of plugs into an adverse atmosphere. The beater plugs can be cleaned numerous times, for any action, and a new, or good set of plugs are not sacrificed. You can even use the beaters to clean the engine out after oil pump priming, carbs too rich, anything to clean the engine out.

Making progress ... check valve leaking solved!

I looked at the seat as best I could with a magnifying glass and determined it looked fairly even - and not very wide, but oxidized/dark.
So I decided to do a "light" lapping with 600 grit compound using and old steel ball soldered to the end of a 1/8" brass tube.
I put the valve body in the vise - then gently and carefully twirled the tube about 4-5 seconds back and forth between fingers with light pressure.
When examining the ball after this, i could see a dark circle where the compound had removed the oxidation. I recoated ball with a bit of compound and repeated 1 more time.

I cleaned & reassembled - filled line with oil and they now were holding 24 hours with no leaks! So I am thinking this did the trick ...

I also retested the output of the pump and with the new springs - it seems the output was unaffected (at least not measureable) by the new springs. I had thought it might reduce the amount of oil output since the valve might close better/quicker with the stronger spring, but it did not seem so. The output was still on the upper end of range @~ 7 cc in 3 min at 2000 rpm (780 rpm @ pump).

So the pump and lines are back on ... off to the next step ... adjustments to the carbs cables etc. ... some fresh gas in the tank and we'll see if she fires up.

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'72 H2 - '72 H2 - '72 H2 - '00 ZRX1100

To your question earlier, yes, Final finish on these seats must be ream hole to get final sharp edge.

Any burrs are a no,no so a coining or light lap seat purchase is a must. Mind you, more of the clean-up of the burrs via lapping will cause leaking again.

These balls are not round, not defect free and not guided except for the spring that is in not way concentric or guided.

Seems like a conformal seat is in order. like yamaha, but those may shift pop-off psi with use.(no experience.

cliff