Size
Bore 92 95 96 97 98 99 100 101 102 103 104 105 106 107 108
Stroke

4000fpm
5000fpm

                             
69.2

8809
11,012

920cc
56.1ci
980cc
59.8ci
1001cc
61.6ci
1023cc
62.4ci
1044cc
63.7ci
1065cc
65ci
1087cc
66.3ci
1109cc
67.7ci
1131cc
69ci
1153cc
70.4ci
1176cc
71.7ci
1198cc
73.1ci
1221cc
74.5ci
1244cc
75.9ci
1268cc
77.4ci
75

8128
10,160

997cc
60.8ci
1063cc
64.9ci
1086cc
66.3ci
1108cc
67.6ci
1131cc
69ci
1155cc
70.5ci
1178cc
71.9ci
1202cc
73.4ci
1226cc
74.8ci
1249cc
76.2ci
1274cc
77.7ci
1299cc
79.3ci
1324cc
80.7ci
1349cc
82.3ci
1374cc
83.4ci
84

7257
9071

1117cc
68.2ci
1191cc
72.7ci
1216cc
74.2ci
1241cc
75,8ci
1267cc
77.3ci
1293cc
78.9ci
1319cc
80.5ci
1346cc
82.1ci
1373cc
83.8ci
1399cc
85.2ci
1427cc
87.1ci
1455cc
88.8ci
1483cc
90.5ci
1511cc
92.ci
1539cc
93.9ci
87

7007
8759

1157cc
70.6ci
1233cc
75.2ci
1259cc
76.8ci
1286cc
78.5ci
1312cc
80.1ci
1339cc
81.7ci
1367cc
83.4ci
1394cc
85.1ci
1422cc
86.8ci
1449cc
88.5ci
1478cc
90.2ci
1507cc
92ci
1536cc
93.8ci
1565cc
95.5ci
1594cc
97.3ci
89

6849
8562

1183cc
72.2ci
1262cc
77ci
1288cc
78.6ci
1315cc
80.3ci
1343cc
81.9ci
1370cc
83.6ci
1398cc
85.3ci
1426cc
87ci
1454cc
88.7ci
1483cc
90.5ci
1512cc
92.3ci
1541cc
94ci
1571cc
95.9ci
1601cc
97.7ci
1631cc
99.5ci

Redline is reckoned at a piston speed of 4000 feet per minute.   High-chrome valve springs, lighter valves, and other modifications can raise this to 5000fpm, no problem. Modern European twins exceed 5500 FPM; Formula One car engines pass 6500FPM. We feel that the tensioner/slippers reach breaking frequency at 11500RPM and the hard-to-find mains seize at 12000RPM


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