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Message: [QUOTE="cujet, post: 252128, member: 19501"] Interesting to think about. The BMEP goes up at lower RPM and therefore there may be more stress on certain components such as piston rings. Higher pressure loads the rings against the bore, however, con rod bearings see more stress at higher revs, as the inertia loads the bearings. Valves and such see higher stress at higher revs. I believe the answer is that generally higher revs result in shorter engine life. However, load is a big factor also. In the distant past, there were a few motorcycle engines that were made in 1, 2 and 4 cylinder versions. The 124cc 1 cyl versions always had a short life, the multi's lasted much longer. I believe this was due to overall engine load. The multi's did not need to have large throttle openings or high revs to achieve the necessary output. Chris [/QUOTE]