EvilBanshee Posted May 2, 2012 Author Report Share Posted May 2, 2012 thats from above the exh port. different ball of wax than measuring from the full stroke. i dont see why people get so stumped on this comrpession ratio shit. put piston at TDC, pour oil through the plug hole until it gets to the threads, record how much oil you poured in. total cylinder volume+ amount of oil you poured in the plug hole divided by the amount of oil your poured in the plug hole. if you want to know the japanese method then pour oil in from where the piston is at the top of the exh port Thats exactly what i did. Pour'd oil down the head when the motor was a TDC. I ended up with 14:1 Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted May 2, 2012 Report Share Posted May 2, 2012 Keep it coming...im learning something here Quote Link to comment Share on other sites More sharing options...
registered user Posted May 3, 2012 Report Share Posted May 3, 2012 (edited) if you layed a piece of plexi glass across your dome and poured in oil you may have a 22cc total volume. once you put the head on the engine and piston is at TDC you will be pouring in less oil because the piston crown is now taking up some of that volume. if your 14:1 was done correct, you would of poured in roughly 16cc like mentioned before. and i might of steered you wrong on the first page, 2cc smaller dome would raise the CR ratio by two numbers. example 10:1 to 12:1 Edited May 3, 2012 by registered user Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted May 3, 2012 Author Report Share Posted May 3, 2012 I do believe it was done correct. My buddy has been a small engine mechanic for 35 years... Hes a very smart guy. Quote Link to comment Share on other sites More sharing options...
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