# Compression Testing?????????



## JTaylor11 (Jul 16, 2009)

What psi should I get while doing a compression test. I have something beating lose in the bottom end and holding bout 45# with about 3 turn overs. But with acouple more she`ll bump upto 60#.


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## phreebsd (Dec 16, 2004)

_Cylinder Compression Measurement_
*NOTE*​ 
_○_
​_Use the battery which is fully charged._

•Warm up the engine thoroughly, and stop the engine. 

•Remove the spark plug (see Electrical System chapter). 
•Attach the compression gauge [A] and adapter *firmly*
*into the spark plug hole.*
*•**Hold the throttle wide open and crank the engine with the*​
*electric starter or the recoil starter several times.*​​​


*When the gauge stops rising, stop cranking and read the*
*gauge.*​


*Cylinder Compression (Usable Range)​​​​​​*​*
*

*Electric Starter: ​​​*​
*(36∼ 66 psi) @380 r/min (rpm)*


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## lg07brute (Jul 20, 2009)

not sure but that seems aweful low. my old popo was around 100 i believe. havent ever checked the brute tho.


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## JTaylor11 (Jul 16, 2009)

Thanks for the info. I did some searching and never could find those number. But I did read somewhere that these BF does have a low compression reading.


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## Yesterday (Jan 2, 2009)

JTaylor11 said:


> Thanks for the info. I did some searching and never could find those number. But I did read somewhere that these BF does have a low compression reading.


 correct


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## IBBruin (Feb 10, 2009)

I'm not 100% sure it's the same on the Brute but my P700 has a centrifugal compression release. As the cam spins faster, weights on the cam gear spin outward and lowers pins set into the cam lobe. While turning over to start, the compression is reduced for easier starting.


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## drtyTshrt (May 27, 2009)

I think our cams have what is called and "easy spin". It is a flat spot on the cam that holds the valve open a few degrees extra to let off some of the compression for easier starting. We have these areas on my go kart cams. The angles are so steep on these cams that it actually throws the valve off of the cam to "float" it. that is how we get around the valve lift height rule. The valve will kiss the top of the cyliner head. If we did not have the easy spin area you would pull your arm out of socket from the compression snap back.


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## IBBruin (Feb 10, 2009)

I was wondering if Kawie changed it from the 04-700 and it looks like it's still a part of the V-Twin. This is from an 05-750 Brute and it's identical.


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## hondarecoveryman (Feb 28, 2009)

I read a thread on kawieriders that mentioned removing these weights that IBBruin is talking about , said it helped on the bottom end :thinking:


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## drtyTshrt (May 27, 2009)

IBBruin said:


> I was wondering if Kawie changed it from the 04-700 and it looks like it's still a part of the V-Twin. This is from an 05-750 Brute and it's identical.


Thanks I thought I did not really know what I was talking about. Thats how I learn by people correcting my mistaken info.


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## IBBruin (Feb 10, 2009)

drtyTshrt said:


> Thanks I thought I did not really know what I was talking about. Thats how I learn by people correcting my mistaken info.


No worries bro, we all should never stop learning. I try to learn something new every day. 

Any man who thinks he knows EVERTHING needs to be shot and put out of our misery.


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## FABMAN (Dec 18, 2008)

IBBruin said:


> I was wondering if Kawie changed it from the 04-700 and it looks like it's still a part of the V-Twin. This is from an 05-750 Brute and it's identical.


Witch part are you referring to? p# 13042?


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## IBBruin (Feb 10, 2009)

I was really only referencing the weight and pin design between the 700 Prairie and the Brute. I didn't check actual part numbers only the way the weights spin out under force and lower the pin into the cam lobe.


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## IBBruin (Feb 10, 2009)

hondarecoveryman said:


> I read a thread on kawieriders that mentioned removing these weights that IBBruin is talking about , said it helped on the bottom end :thinking:


What are they saying about that? I would think any rpm's over cranking speed the weights would swing out allowing the pin to drop back into the cam and give it full compression at idle. It seems to me by taking the weights out would give it full compression while you were trying to crank it and it would be a SOB to start.


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## FABMAN (Dec 18, 2008)

Id like to know too. The #s I'm referring to are in the pic you put up ibbruin. I'm just trying to figure out exactly how it works.


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## IBBruin (Feb 10, 2009)

This is the way I understand it. I've never had the camshaft apart but have had it in my hand and played with the weights and watched the pin move up and down.


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## hondarecoveryman (Feb 28, 2009)

Less rotating mass is the only advantage i could come up with for removing them , But I aint that power crazy ......yet :haha:


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## FABMAN (Dec 18, 2008)

IBBruin said:


> This is the way I understand it. I've never had the camshaft apart but have had it in my hand and played with the weights and watched the pin move up and down.


 That's what I thought and now I know thanks. Now what I'm wondering is what it the compression after the compression relief kicks out?


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