Quote:
Originally Posted by pete
The push rods are light but still have mass that is traveling in a
linar motion and has to be stoped then returned in the oppisite direction..
A over head cam shaft dose have a lot more mass but is dynamic & dose not require
stoping to change direction like push rods..
..
|
What you say is true. And on a street engine it is important. And of course, racing engines. As to the advantages of an overhead cam engine for a dual-sport/enduro, my experience is that they are over rated. What is needed is low-mid range grunt, which is easy to get with overhead valves. It would be just as easy to get with an overhead cam engine, if it was designed to the same protocal. But they are not. They are designed to take advantage of their lighter valve gear at high rpms. And their power curve reflects this. I used to be involved in road racing, after my time playing with 500 Goldstars on American flat tracks. The AMA changed the rules (from 500 overheads vs 750 flatheads to 750 overheads),so I lost interest. I was a great believer in the advantages of overhead cam engines, so I bought a 250 Ducati. Did fairly well for a while until I got my plow cleaned by Moto Parilla's and Aermacci Harley Davidsons. Both of those 250's were pushrod OHV engines. The real advantage of overhead cam engines comes at 350cc and bigger, for road racing.