Cylinder compression psi
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Joined: Aug 2013
Posts: 84
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From: Tampa, Florida
Cylinder compression psi
What would be a normal psi compression for a 1991 EVO 1340 cc engine. As far as I know the engine is unmodified stock. I am getting 155 on each cylinder. after about 1 minute they each drop down to about 145.
Does this seem about right?
Does this seem about right?
HDF Community Team
Joined: Dec 2005
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From: NC USA
Not sure whether you mean they each drop down on the gauge (without releasing the pressure) or if you mean they check 155, then a minute later check 145.... (?)
Either way, those compression numbers are totally normal/good.
Either way, those compression numbers are totally normal/good.
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Joined: Aug 2013
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From: Tampa, Florida
I bought it in 1995, it had 23,000 miles. It now has 58,000 I don't know for sure it is stock. I bought it from a second hand shop, they said it was stock.
I was testing the compression because it would not start. I checked the spark and then the compression. I found the problem with the carburetor.
The day before I went to start it and it backfired really loud. The carburetor was separated from the manifold. I fixed that then was able to start it.
After a few seconds I shut it off and charged up the battery. When I went to start it again, the starter clicked and the bike went dead. No lights or
anything. I think I blew a fuse or tripped a circuit breaker or something. When it clicked I thought I saw a flash of light out of the corner of my eye.
In the vicinity of the battery. When I was testing the compression the engine was cold. It had not run since the day before. Since I started this story
I might as well ask, does anyone have any ideas about the dead bike. Battery is good, but nothing comes on when I turn on the switch.
I was testing the compression because it would not start. I checked the spark and then the compression. I found the problem with the carburetor.
The day before I went to start it and it backfired really loud. The carburetor was separated from the manifold. I fixed that then was able to start it.
After a few seconds I shut it off and charged up the battery. When I went to start it again, the starter clicked and the bike went dead. No lights or
anything. I think I blew a fuse or tripped a circuit breaker or something. When it clicked I thought I saw a flash of light out of the corner of my eye.
In the vicinity of the battery. When I was testing the compression the engine was cold. It had not run since the day before. Since I started this story
I might as well ask, does anyone have any ideas about the dead bike. Battery is good, but nothing comes on when I turn on the switch.
Last edited by BigT-91; Feb 15, 2020 at 10:55 PM.
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Road Warrior
Joined: Dec 2007
Posts: 1,286
Likes: 64
From: SoCal
Sparking at the battery tells me you very well may have loose/dirty connections for your battery cables.
It's a reasonable place to start looking for the problem.
If the carburetor blew off the manifold that tells me the carburetor is not supported sufficiently.
It should not be supported by the manifold rubber connection only.
It's a reasonable place to start looking for the problem.
If the carburetor blew off the manifold that tells me the carburetor is not supported sufficiently.
It should not be supported by the manifold rubber connection only.
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Thread Starter
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Advanced
Joined: Aug 2013
Posts: 84
Likes: 33
From: Tampa, Florida
Sparking at the battery tells me you very well may have loose/dirty connections for your battery cables.
It's a reasonable place to start looking for the problem.
If the carburetor blew off the manifold that tells me the carburetor is not supported sufficiently.
It should not be supported by the manifold rubber connection only.
It's a reasonable place to start looking for the problem.
If the carburetor blew off the manifold that tells me the carburetor is not supported sufficiently.
It should not be supported by the manifold rubber connection only.
by the air cleaner unit and it was tight. The backfire was tremendous. I never had one that loud before. It scared the s**t out of me.
