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Offline l3o

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low compression question
« on: March 16, 2011, 04:47:06 PM »
I have owned this 1975 cb550 for a couple years... I have ridden it quite a bit.  I ordered a compression test kit a couple years ago, but it didn't come with the right adapter so I put it off until today - when I received the adapter in the mail.  Testing cold the thing reads all around 60psi.  Throttle wide open.  I put some oil in a cylinder and it jumped up to like 110psi.  (So, that would indicate rings are messed up, right?)  However, it starts right up and has plenty of power.

I realize a warm engine would read a bit higher, but should I be able to operate the bike fine at that PSI?

Thanks.
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Offline TwoTired

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Re: low compression question
« Reply #1 on: March 16, 2011, 04:51:51 PM »
How much oil did you add to a 15cc combustion nchamber?

http://forums.sohc4.net/index.php?topic=369.msg476032#msg476032
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Lloyd... (SOHC4 #11 Original Mail List)
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Offline l3o

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Re: low compression question
« Reply #2 on: March 16, 2011, 05:14:24 PM »
Thanks for the link.  Not sure why I didn't see that when searching. 

So, my automotive compression gauge is effectively useless to measure the actual PSI - it's only benefit is to measure difference between cylinders.

I probably put half a tablespoon of oil in the cylinder...

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