Kawi2strokes.com Forum

You should test each cylinder individually. It's only if you have a crankshaft with aluminum labyrinth seals that you need to test all three at once. That's because the aluminum seals allow leakage with the engine not running.

How long did each cylinder hold the pressure? My H2crank seals were so bad when I had it rebuilt that I'm sure it would not have held pressure at all.

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If it surges, that's normal, upshift.

We're using this adapter going from the Mityvac to the spark plug hole: https://www.sealey.co.uk/product/5637204961/compressed-air-adaptor

All cylinder heads torqued to spec.

We tested the right cylinder on the H1B first. Unable to build pressure. We demounted the cylinder head and saw the gasket had been leaking. So we replaced the gasket with a solid piece of rubber (sealing off the top end). Pressure could be built now but did drop slowly. Then we made a hole in the middle of the rubber piece (opening everything up). Again we're unable to build pressure.

The left cylinder was the same, we couldn't pump up pressure.

Going to the H1D, we tested the left cylinder. On that one pressure could be built to 6 psi. It did drop to 4,5-5 psi in about 6 minutes. The vacuum test it failed totally.

If you replaced the head gasket with a rubber sheet, how did you get any pressure into that cylinder from the spark plug hole?

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If it surges, that's normal, upshift.

We did that on purpose just to see if the spark plug hole adapter, nipple and hose from the pump were okay.

But the pressure did drop slowly even then so that probably needs to be taken into account.

OK, I get it.

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If it surges, that's normal, upshift.

I have never done a cylinder pressure test like that. The only two types of ring leakage tests are pumping, where you get to a certain PSI, around 160 would be good, by kicking it over, or a cylinder leakdown test (almost always for four strokes) that measures flow, you will see leakages under 10 percent maybe. For these bikes, the "kick with a pressure guage in the plug hole and wide open throttle" is the accepted method. This is not what you are doing. For crankcase leakage, you were supposed to do a vacuum test on individual crankcases, with stock seals.
I do have to applaud you for the longest running thread on a single topic, on this board and i'm sure, on any bike or automotive help board on the entire internet.

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

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If it surges, that's normal, upshift.

LOL! Ok, second longest thread....!

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1974 Kawasaki H2B 750, 1981 Yamaha XV750 Cafe, 1986 Kawasaki KDX200, 2003 Honda XR100, 2004 SDG140. 2006 Ninja 500R Turbo intercooled fuel injected.

We are doing crankcase tests. Two Dorman plugs for inlet and exhaust, one nut and gasket for the oil line and piston at bottom.

The H1B had the same problem as the H1D, that is not running on the center cylinder.

The H1B now had the engine completely rebuilt and runs great.

The crank seals were completely dried out.

The H1D engine is going to have the same treatment too.