Cool Head?

• Cool Head?
  Posted by CrustyOreo on 02 Jul, 2013 10:54
• I'm 100% new to the 2 stroke world. What are these "Cool heads" I see online? Benefits? Some of them have different CC ratings? What's the meaning behind this?
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• #1 Reply
  Posted by QuadMan8 on 02 Jul, 2013 11:16
• CC rating is the size of the combustion chamber/dome.  They have removable replaceable domes where one can change compression for elevation or fuel or type of build etc..  The term cool head leads people to believe that they cool better than a stock head but builders say the cooling is the same---perpaps they just look cool.   In any event--for the zilla one would still need to have the domes correctly modified or cut for a proper squish band clearence as you would on any factory head.   A popular modification to the cool head ( or any head) is to have it cut for 0-rings.  This eliminates the need to use expensive head gaskets and you can re use the o ring. Some say the 0-ring seals better than stock gasket as well. 
  
  A properly set up cool head will not perform any better or worse than a properly set up stock head.
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• #2 Reply
  Posted by Motoman991 on 02 Jul, 2013 12:13
• The only benefit to a cool head is being able to switch domes. 
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• #3 Reply
  Posted by Q2W on 02 Jul, 2013 14:14
• Quote from: Motoman991 on 02 Jul, 2013 12:13

  The only benefit to a cool head is being able to switch domes. 
  

  
  is that a benefit?
  
  

  Quote from: MotorGeek on 27 Jun, 2013 08:48

  Why to you want to screw up your engine design by using the right head one day and the wrong head another day.   
  
  It is the total engine design: ports, pipe, reeds, carb head and ignition timing that determines what octane fuel your engine needs.
  
  Just changing the compression ratio does not have a large influence on the octane rating that your engine needs unless you reduce the compression to the point that it makes power like a 250.  If you reduce your compression ratio this much, your pipe and ports will be a mile out of tune with each other. 
  
  Most of this stuff about using different heads or domes so that you can have a engine that can run on any fuel began when the billett heads were first started.  I am not sure if was a marketing campaign to sell you more domes after you bought a billet shell or if it was absolute ignorance about the intricate design and understanding of high performance two strokes on the part of the billet head industry. 
  
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• #4 Reply
  Posted by QuadMan8 on 02 Jul, 2013 16:07
• yEs its a benefit if you change altitude.  I ride from 1000 foot to 13,000 foot (Not on the same weekend)  An engine is built to perform at a certian compression.  If that is drematically changed performance will be affected.  I have two domes cut/ squish modified .  for people running at same altitude then I agree there would be no benefit.
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