Worn Rings and/or Valve Guide Seals

  • daveo
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23 Mar 2018 18:53 #780705 by daveo
Having to add oil often after 20K well-ridden miles since Spring 2015.

Maybe ring time, but wondering about the Viton seals which were installed in the head that got installed with a set of 84 ZX cams at the same time in 2015.
Could the different cam lift cause accelerated seal wear, considering the valve stems were worn-in from the start with standard KZ1100/1000 camshafts?
The head and valves had 8K miles on them when installed, so valve stem wear would have been minimal.

Hadn't noticed oil on the stems when viewed through the ports last opportunity when the carb holders and exhaust were off in the past year or so.

Thoughts and suggestions appreciated.

:)

1982 KZ1100-A2

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  • Street Fighter LTD
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23 Mar 2018 19:13 #780707 by Street Fighter LTD
Replied by Street Fighter LTD on topic Worn Rings and/or Valve Guide Seals
Compression test and cylinder pressures ?? Try dry and wet and compare numbers.
Cylinder Leak down tests and results ??
Inquiring minds want to know
Dave


Original owner 78 1000 LTD
Mr Turbo Race Kit, MTC 1075 Turbo pistons by PitStop Performance , Falicon Ultra Lite Super Crank, APE everything. Les Holt @ PDM's Billet Goodies . Frame by Chuck Kurzawa @ Logghe Chassis . Deep sump 5qt oil pan. RIP Bill Hahn

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23 Mar 2018 19:41 #780709 by 650ed
Replied by 650ed on topic Worn Rings and/or Valve Guide Seals
A leak down test should show if the rings and/or valves are leaking compression. Also, a compression test can show issues, but be SURE to follow the instructions in the Kawasaki Service Manual or the results of the test may be misleading.

If you decide to do a "wet" compression test by adding oil to the cylinders consider the following. Even a very small amount of oil added to a cylinder can make a big difference in the compression readings. I have seen more than one person advocate adding "about a teaspoon" of oil to each cylinder when doing a "wet" compression test. That may not sound like much oil to many folks, but a teaspoon is actually right around 5cc, and that is a lot. As an example of how little oil it takes to change the compression ratio I offer the following diagram. It uses a hypothetical cylinder with a total volume (cylinder & head) of 100cc and a dry compression ratio of 10:1. A little oil added changes things quite a bit, so if different amounts of oil were added to different cylinders one can see that the compression ratios might vary a lot. This example is not precise and is not any specific engine and it doesn't take into account oil that may seep past the rings, etc. It only is meant to demonstrate in very general terms how adding oil can change compression ratios even in a perfect engine. You can see how quickly the compression ratio jumps as a little oil is added to the cylinder. Ed






1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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23 Mar 2018 20:29 #780712 by Nebr_Rex
Replied by Nebr_Rex on topic Worn Rings and/or Valve Guide Seals

Street Fighter LTD wrote: Compression test and cylinder pressures ?? Try dry and wet and compare numbers.
Cylinder Leak down tests and results ??
Inquiring minds want to know
Dave


+1

2002 ZRX1200R
81 GPz1100
79 KZ1000st daily ride
79 KZ1000mk2 prodject
78 KZ650sr
78 KZ650b
81 KZ750e
80 KZ750ltd
77 KZ400/440 cafe project
76 KZ400/440 Fuel Injected

www.dotheton.com/forum/index.php?topic=39120.0


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  • daveo
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24 Mar 2018 09:19 #780725 by daveo
Replied by daveo on topic Worn Rings and/or Valve Guide Seals
What is the purpose of adding a small quantity of oil to the cylinders? Is it primarily meant to reduce the space in the combustion chamber at TDC as 650ed mentioned, or temporarily improve the seal of the rings at the cylinder wall as well?
I do not have access to a leak-down test tool, but do own an Autozone compression test gauge that has a pressure release valve.

1982 KZ1100-A2

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  • SWest
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24 Mar 2018 11:20 #780732 by SWest
Replied by SWest on topic Worn Rings and/or Valve Guide Seals
A small amount of oil is to see if the compression comes up indicating bad rings.
Steve

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24 Mar 2018 12:47 #780736 by ajsfirehawk
Replied by ajsfirehawk on topic Worn Rings and/or Valve Guide Seals
Right on Steve, just for clarity Steve isn't talking about 2 or 3lbs improvement in compression, you are talking 10 -15lbs or more, correct Steve?

79 KZ650 SR
80 KZ1000 Z1 Classic
83 KZ1100 LTD
Z900RS
23 Mach 1

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24 Mar 2018 15:06 #780742 by SWest
The following user(s) said Thank You: mopguy

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