Re: Details on Honda
OK, time to help those engineering-challenged posters out there:
1) The bore/stroke ratio for the Honda is 1.546 and the Yamaha is 1.581, making the Honda, a difference of 0.035 or 2.2 percent less oversquare than the Yamaha. Hardly a long-stroke motor.
2) Rocker arms. You see, El Doorknob, weight is a huge issue with dirt bikes. Honda agreed with KTM, Husaberg and Vertemati that the extra cam and its attendant weight and volume were not necessary. Honda did them all one better by directly actuating the intake valves (allowing steeper cam profiles) and using short rockers (similar to Mercedes' Indy500 winning motor of six years ago) to actuate the exhaust valves. This results in a lighter, engine which will be smaller at the top front of the head, allowing for more ideal engine placement.
Why is this important? Well my technically challenged friends, what has the Yamathumper been criticized about? Two things: weight (it's the heaviest mega thumper out there - KTM's electric start 520 is lighter) and slow low speed handling caused by it's largest in class wheelbase and seat height. Honda deals with both of those problems with typical elegance.