More compression
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Joined: Jun 2019
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From: Virginia
More compression
So after having the 124 on my street bob for about a year I'm looking for a little more power. Thinking about +1 heads and a bigger cam but it seems my 10.75 compression is severely limiting my options. Am I thinking right that all I need is some higher compression pistons to achieve what I'm wanting?
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From: Bates County MO
Ported heads and increased compression tend to build the upper RPM HP, but only if you have supporting pieces (bigger cam/springs, better AC + intake/TB/injectors+ pipes).
What's the current combo?
What's the current combo?
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From: Virginia
S&S 475, 62mm throttle body, 7.1 injectors, Arlen ness big sucker, V&H pro pipe
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So after having the 124 on my street bob for about a year I'm looking for a little more power. Thinking about +1 heads and a bigger cam but it seems my 10.75 compression is severely limiting my options. Am I thinking right that all I need is some higher compression pistons to achieve what I'm wanting?
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Joined: Jun 2019
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From: Virginia
Do you really know what your compression is? The HD engine has loose tolerances and due to that, the stock compression will vary +/-0.5. So while you may have an advertised 10.75 it may be 10.25 or 11.25 and anywhere in-between. The only way to really know what you have is to take it apart and measure your parts and then make the proper decision for your new parts. I can tell you that people on the east coast can run with compression ratio's up in the 12.4:1 and it works, but try that out west in So. CA. during the summer months and your **** out of luck. You will have a bike that doesn't want to run below 2500 RPM and it pings anytime your riding around town.
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Cruiser
Joined: Mar 2012
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From: Connecticut
A lot of so call "builders" are no more than plain assemblers. To know what your true compression rate is you need to measure how far your piston is short of the top of the cylinder bore and the exact size of the cylinder head combustion chamber then do the math.
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I hate to say it but most are just changing parts as they do not want to spend the time it takes to measure all the parts and find out.