Compression 110/120

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Marco
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Compression 110/120

Post by Marco » Tue Aug 27, 2019 7:13 pm

Right cylinder tests 110 and left tests 120. Does the difference matter much?
Is that compression reasonably healthy?
The valves were adjusted prior to testing.
2012 Gear Up "Anichka"
19,000 Km

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Lokiboy
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Re: Compression 110/120

Post by Lokiboy » Tue Aug 27, 2019 7:16 pm

Within 10% is considered ok
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
100,000 km and counting

RC20
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Re: Compression 110/120

Post by RC20 » Tue Aug 27, 2019 9:33 pm

Was the test done when the engine was on the hot to warm side?

Seems about 20 lbs low on the 120 side. The side to side difference ok, but then that is more of a split.

Seems 140 is more normal. You might squire some oil in the cylinders and see what that does.

I don't have Ural data but the R80 good was 130 psi, marginal was 108. You look to be at marginal on one and a bit low on the other.

Lots of miles would have a bearing
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Formerly Owned: ( various rides on others)
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Lokiboy
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Re: Compression 110/120

Post by Lokiboy » Tue Aug 27, 2019 10:12 pm

RC20

120 is good for a 7 year old rig. I should know, that’s about what mine is.
2011 Gear Up - "Erika"
Yorktown, VA

Mains: 127, Idle: 40, Needle: 1 shim
MKIII air filter
100,000 km and counting

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Desantnik-VDV
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Re: Compression 110/120

Post by Desantnik-VDV » Tue Aug 27, 2019 11:42 pm

Yeah, old worn out Urals are more loose.
Alex
2007 GearUp - БМД (Боевая Машина Десанта)

The rest is just a History:
2014 Ural M70
1998 Honda f6 GL 1500 Valkyrie Tourer /Champion Escort sidecar
1999 Ural Deco Classic/BMW R100 engine
1980 BMW R100RT (2nd Heart Donor for 1999 Deco for more HP)
1983 BMW R80/7 (1st Heart Donor for 1999 Deco)
2002 Ural Barberian Classic
2003 Honda Shadow ACE
1999 Ural BC (went to US circus in Tokyo to adapt a bear driver)

RC20
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Re: Compression 110/120

Post by RC20 » Wed Aug 28, 2019 1:15 pm

RC20

120 is good for a 7 year old rig. I should know, that’s about what mine is.
Actual reports are worth far more than the listed data.
Fear No Gravel
Formerly Owned: ( various rides on others)
Honda 90
2 x CB750K (one a true Japan Model flown to Hawaii by a P3 Orion Sub Patrol Aircraft!)
1 x CB700 SC ala Shaft Drive Nighthawk S (RC20 is the actual in house production Model)
1 x R80GS (ok to start with, learned to love it for what it was)
1 x CB450K

Current:
1 x 2019 cT Terracotta

What I Did (I quit June 2 , 2019)
Mechanic/Technician/Engineer: Electro Mechanical Systems

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harryball
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Re: Compression 110/120

Post by harryball » Wed Aug 28, 2019 4:54 pm

My 2008 Tourist ran 120/115
My 2010 Patrol ran 125/110
I think what you are seeing is normal.

I have not checked my 2017 rigs, but from what I know I should see 140+ on those. I did try to check them, but my gauge is broken, gives 60psi no matter what it sees. I mean, I only dropped it, twice, then went to pick it up the second time and kicked it across the shop into a lift pylon. :? Was an off day.
---
2017 - cT - "Georgia" My wife's rig.
2017 - M70/Retro, Sigmund. My wife's other rig.
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