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Old Apr 23, 2011 | 09:41 PM
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Default Compression
Maybe someone could help me out? Getting ready to bore my 88 in. to a 95 and put cams in. What compression ratio pistons you guys running when you bore it. I have a 06 Streetglide. THANKS.
 
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Old Apr 23, 2011 | 10:06 PM
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I'd stay at 10.5:1 or less so you won't have detonation issues and run pump gas. Stay with components that compliment each other or you will end up with a "science project" that runs crappy or no telling what. There are several reputable companies that offer kits to take the guess work out of the equation.
 
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Old Apr 23, 2011 | 10:24 PM
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...I would be at 10:1...no higher...
 
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Old Apr 24, 2011 | 08:16 AM
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If i run 10 to 1 will i need compression releases?
 
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Old Apr 24, 2011 | 08:36 AM
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Depends on the cams you run and if you have a high output starter but if were me, I'd put the compression releases in while you have it apart so you won't have to worry about it if you want to change cams again.
 
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Old Apr 24, 2011 | 10:55 AM
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Use SE Race Heads and they will already be ported for CRs. They make a huge difference. I'm runnin 10.5:1 and it starts like a dream after 16000 miles with stock starter.
 
Last edited by coolerman69; Apr 24, 2011 at 11:33 AM. Reason: Wrong comp ratio
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Old Apr 24, 2011 | 11:06 AM
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10.5:1 max...I would do 10:1, it's a very good ratio for these motors. Put in releases..each motor cranks differently depending on your setup, won't hurt to be on the safe side...JMO
 
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Old Apr 24, 2011 | 11:16 AM
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On our 107 I went with a 9.5:1 and glad I did, especially with the uncertainies with current and future fuel. It burns 87 octane well, it seems that it's happening more and more when traveling that I can no longer find 91+ octane fuel, at any price. With the right complementing mods, you can still obtain a high level of performance without the power robbing, destructive fear of detonation.

Originally Posted by CURTYS06FLHX
Maybe someone could help me out? Getting ready to bore my 88 in. to a 95 and put cams in. What compression ratio pistons you guys running when you bore it. I have a 06 Streetglide. THANKS.
 
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Old Apr 24, 2011 | 01:16 PM
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I was thinking Screamin Eagle 9.4:1 flat tops with Andrews 37 gear drive cams.
 
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