I keep an Excel spread sheet that takes bore and stroke as variables and calculates displacement in ccs. Here it is. There is a lot to be learned from this. First of all, look at the trends. Each 1mm increment of bore gives a lot more increase in displacement than a 1mm increase in stroke.
For those of you who want to play around with your own spread sheet, the equation is:
displacement = 0.001*2*stroke*3.1415927*(bore/2)^2
Enjoy.
HTML Code:Displacement vs. Bore and Stroke Combinations for Yamaha 62T/61X-Based Motors All bore and stroke units in millimeters (mm) Bore OEM cc +4mm cc +5mm cc +6mm cc +8mm cc +10mm cc 81.0 68 701 72 742 73 752 74 763 76 783 78 804 81.5 68 709 72 751 73 762 74 772 76 793 78 814 82.0 68 718 72 760 73 771 74 782 76 803 78 824 82.5 68 727 72 770 73 780 74 791 76 813 78 834 83.0 68 736 72 779 73 790 74 801 76 822 78 844 83.5 68 745 72 789 73 799 74 810 76 832 78 854 84.0 68 754 72 798 73 809 74 820 76 842 78 865 84.5 68 763 72 808 73 819 74 830 76 852 78 875 85.0 68 772 72 817 73 828 74 840 76 863 78 885 85.5 68 781 72 827 73 838 74 850 76 873 78 896 86.0 68 790 72 836 73 848 74 860 76 883 78 906 86.5 68 799 72 846 73 858 74 870 76 893 78 917 87.0 68 808 72 856 73 868 74 880 76 904 78 927 87.5 68 818 72 866 73 878 74 890 76 914 78 938 88.0 68 827 72 876 73 888 74 900 76 924 78 949 88.5 68 837 72 886 73 898 74 910 76 935 78 960 89.0 68 846 72 896 73 908 74 921 76 946 78 970 89.5 68 856 72 906 73 919 74 931 76 956 78 981 90.0 68 865 72 916 73 929 74 942 76 967 78 992 90.5 68 875 72 926 73 939 74 952 76 978 78 1003 91.0 68 885 72 937 73 950 74 963 76 989 78 1015 91.5 68 894 72 947 73 960 74 973 76 999 78 1026 92.0 68 904 72 957 73 971 74 984 76 1010 78 1037
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Originally Posted by cookerq62
