Author Topic: Pressure test kit.  (Read 882 times)

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Online Alistair64

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Re: Pressure test kit.
« Reply #30 on: October 29, 2020, 08:27:36 AM »
Great stuff. Think I'm now armed with everything I need to know... some of us just take a little longer to get there  ;D
Yes, the gauge is a beauty and may well go for one myself.
Thanks also to JohnnyRD for a heads up on a thread from the other section.
Guess I should have searched on there too.
Will have a read and take my time (just as I did when fitting the Powerdynamo kit).
You've all been a great help guys, so many thanks again.
Hope I have no more questions (for now at least)  :)
1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Offline pidjones

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Re: Pressure test kit.
« Reply #31 on: October 29, 2020, 10:30:59 AM »
https://www.ebay.co.uk/itm/JSC-PlumBest-Jones-Stephens-Corp-Gas-Test-Gauge-Assembly-G64-015-15-PSI-New/372427212419?epid=673161148&hash=item56b6644683:g:lqgAAOSwDJRbkEjG

If I were to buy something 'off the shelf', it would look similar to the above, but it's from the U.S. and I've no idea what a 3/4 MPT connection is on the other end of the T.
Plumbing/pneumatic threads...why are so many and why is this so confusing?   :'(
NPT are sized by ID, so a 3/4" NPT would be huge for this application. I was lucky that a cheap tool vendor here - Harbor Freight - sells an inexpensive compound gauge with barbed fittings and tubing as a non-fuel injection fuel pump/manifold vacuum kit for $15.99 US. I've had it for years and used it for many things. Some old brass rounds that I had from years ago projects, spun down in the lathe and one drilled and tapped for a plastic 1/4" barbed fitting that was in my plumbing drawer. Sometimes it pays to never throw things out!
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Offline Astute Greaser

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Re: Pressure test kit.
« Reply #32 on: October 29, 2020, 10:44:32 AM »
Could you not use a car foot pump.
https://www.halfords.com/tools/garage-equipment/tyre-inflators-and-pressure-gauges/halfords-essential-twin-barrel-foot-pump-and-gauge-686646.html

That has the gauge, length of hose and Schrader connection plus its your pressure source. The gauge maybe not that accurate in its readings but its showing pressure drop - detecting leak overtime that's the point. Not professional but ....
-Mike
« Last Edit: October 29, 2020, 10:47:55 AM by Astute Greaser »

Offline ajh

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Re: Pressure test kit.
« Reply #33 on: October 29, 2020, 12:42:29 PM »
Could you not use a car foot pump.
https://www.halfords.com/tools/garage-equipment/tyre-inflators-and-pressure-gauges/halfords-essential-twin-barrel-foot-pump-and-gauge-686646.html

That has the gauge, length of hose and Schrader connection plus its your pressure source. The gauge maybe not that accurate in its readings but its showing pressure drop - detecting leak overtime that's the point. Not professional but ....
-Mike

+1, thats what I use on my cheap setup detailed ealrier in the thread. Or  pump it up and then just use a more accurate tyre guage to check the pressure every 5 mins
in Chiswick, West London

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Online Johncb500

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Re: Pressure test kit.
« Reply #34 on: November 10, 2020, 11:39:11 AM »
Got my kit assembled. As well as some gasket card.

Just need some enthusiasm to do something

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Offline Lyonsio

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Re: Pressure test kit.
« Reply #35 on: November 21, 2020, 09:49:35 PM »
Do the oil supply ports leak out through the pump? I know there’s a check valve in the system but not sure it can cope with positive pressure for very long? Anyway I think I need to make up my own kit for the 200

Offline pidjones

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Re: Pressure test kit.
« Reply #36 on: November 21, 2020, 09:55:00 PM »
Do the oil supply ports leak out through the pump? I know there’s a check valve in the system but not sure it can cope with positive pressure for very long? Anyway I think I need to make up my own kit for the 200
Carbs need to be  pulled and intakes plugged to do the pressure test.
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Online Johncb500

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Re: Pressure test kit.
« Reply #37 on: November 24, 2020, 05:06:37 PM »
Did pressure check today.

Sealed both inlets. Set LH at BDC.and pressured it. Virtually no seal.dropped in about 10secs.

Blanked RH cylinder as well. Pressure held for twice as long.

Then did test on RH cylinder. Very similar results. Sealed LH pot and again got a better result. No sign of air leaks.

Disappointed. The engine was rebuilt. New crank.seals etc about 2k miles ago.

Guessing needs new crank seals.


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Offline NivagRD

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Re: Pressure test kit.
« Reply #38 on: November 24, 2020, 08:09:22 PM »
John, we both exhaust ports plugged for the duration of your tests? Did the bike seem to run OK before the tests? What is the compression pressure on each cylinder with the throttle wide open and the engine warmed up just before the spark plugs were removed? Thanks, Gavin
1973 LS2, 1980 RD200DX, 2019 CB650R.

Online Johncb500

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Re: Pressure test kit.
« Reply #39 on: November 24, 2020, 09:06:14 PM »
John, we both exhaust ports plugged for the duration of your tests? Did the bike seem to run OK before the tests? What is the compression pressure on each cylinder with the throttle wide open and the engine warmed up just before the spark plugs were removed? Thanks, Gavin
The exhausts were plugged alternatively and separately.

The bike ran ok.but had no "sparkly".would only pull top gear downhill.

Never done a compression test.
And the plugs were in when the crankcase pressure was tested

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Online Alistair64

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Re: Pressure test kit.
« Reply #40 on: November 24, 2020, 09:16:02 PM »
When testing one cylinder, do both inlets and exhausts need to be plugged?
I'm not as clued up on this as many of you, so you may have to explain to this 'pressure test idiot'  :'(
I'm assuming the large o-ring on the centre web of the crankshaft should isolate one cylinder from the other, but is there anything else which does?
By plugging both cylinders at the same time, are you ignoring the integrity of this o-ring?
In other words, if the test is bad with just one cylinder plugged, but good with both plugged, would this mean that the o-ring is worn?

Thanks.
1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Online Johncb500

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Re: Pressure test kit.
« Reply #41 on: November 24, 2020, 09:21:01 PM »
When testing one cylinder, do both inlets and exhausts need to be plugged?
I'm not as clued up on this as many of you, so you may have to explain to this 'pressure test idiot'  :'(
I'm assuming the large o-ring on the centre web of the crankshaft should isolate one cylinder from the other, but is there anything else which does?
By plugging both cylinders at the same time, are you ignoring the integrity of this o-ring?
In other words, if the test is bad with just one cylinder plugged, but good with both plugged, would this mean that the o-ring is worn?

Thanks.
That is why I tested both separately and then together.

I believe the inner seal is not like the outside seals. And it works differently.

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Offline NivagRD

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Re: Pressure test kit.
« Reply #42 on: November 24, 2020, 09:46:10 PM »
Both exhaust ports need to be plugged for the test. The seal at the centre of the crank is a labyrinth (the "O" ring is around the outside of the labyrinth seal block). The labyrinth seal does not provide a 100 percent sealing integrity when the engine is static. As such there is a path from the cavity under one piston to the cavity under the other. Depending on the position of the pistons (180 degrees opposed), there could be a path up through the transfer ports and out of the exhaust port - hence need to plug both exhaust ports.
1973 LS2, 1980 RD200DX, 2019 CB650R.

Online Alistair64

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Re: Pressure test kit.
« Reply #43 on: Today at 09:58:26 AM »
Ok, thanks guys.
Wish I'd have known this when I ordered an expansion plug for the exhaust port from the States for a princely sum (strangely couldn't find any over here).
The cost is mainly in the postage, so I should have ordered two  :'(

I take it it's not necessary to plug the other inlet to the one you are blowing air into?
Because there's no potential route out for the air?

1982 Candy red RD200DX
1983 Yellow/black RD200DX (resprayed and previously owned by another forum member)
1986 White/red RD350F1 YPVS - owned since 1987...yes, honestly!!

Online Johncb500

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Re: Pressure test kit.
« Reply #44 on: Today at 10:43:07 AM »
Ok, thanks guys.
Wish I'd have known this when I ordered an expansion plug for the exhaust port from the States for a princely sum (strangely couldn't find any over here).
The cost is mainly in the postage, so I should have ordered two  :'(

I take it it's not necessary to plug the other inlet to the one you are blowing air into?
Because there's no potential route out for the air?
I think you need to block the inlets as well.




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