Leave it to Honda to short cut the performance envelope ! Rocker arms? Come on, thats going backwards in development. Long stroke engine, take a chance and let the dam bike rip instead of just keeping up with the pack. Like the 929 (I owned one) it could have been more in the engine department, but Mr. greenpeace Honda was afraid of hurting someones feelings in the community that they were building death machines and they just can't have that ! Pussies !! Yamaha has the right idea when it comes to performance, Let em rip!!, and I've owned Hondas more than any other brand, so this is not a one sided view. Look at the fourstroke shoot outs and the YZ426 is trashing the other BIGGER engined thumpers because it rips and has QUALITY suspension ! So, Honda take off the dam gloves and give us a rip snortin,gound shakin bike for once !
It's not a question anymore "if" they are going to do this. Honda decided to drop 2 strokes altogether, so a MX thumper is going to be necessary.
Personally, the type of bike I'd most like to see would be a RSF450R road racer . . . A friend of mine has a very-built XR600 motor in an old TZ250 frame, and if the quality of that bike could be raised to production standards, it would rule! I doubt that Honda will send something like that to the land of "bigger-is-better", though . . .
I have also owned more Honda's than any other brand, and have been generally happy with them. HOWEVER, they are always so damn PC that I'm just about sick of it! Honda: Stop selling underpowered engines! Just look at the long line of under-powered, but otherwise highly competent, "unoffensive" bikes:
CB-1 CBR900 after '94
VTR1000 and more . . .
The last three bikes I've bought have been Suzuki's, and that's not going to change unless Honda sends something a little more exciting . . .
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.
All you've written is true BUT SOHC with rockers will never hold valve clearance as acurately or for as long as direct camshaft to valve actuation. In other words the Honda will require more frequent adjustment and replacement of valve train gear. Yahama always makes uncompromisingly reliable motors thant don't ever require much maintenance, even if they have to get more complicated to do it (ie: 5 valves,DOHC)
Have you ever driven, read about, or even seen a car with a VTEC engine?
The S2000 has the fastest piston speed of any production car in the world, and produces 110 hp per liter. You can argue that it's not meeting its potential, but you can count the number of normally aspirated cars that produce more power per displacement on the fingers of one hand with room left over.
By the way, Honda does not claim to have no warranty claims on their VTEC engines. They say they have never seen a VTEC system failure or the failure of another engine system caused by the VTEC system. BIG difference.
oh yeah, and valvesprings are real high tech. the only way to really advance valvetrain systems right now is by hydraulic or electrical actuation. Rocker arms are perfectly suitable for the application.
you hit the nail right on the head my friend. these four stroke pigs trying to compete with the 2strokes make me sick. actually, their designers and the people who love them make me sick. not only do they sound worse than any briggs and stratton mini-bike i ever owned, but they remind me every time i look at them just how far the EPA has gone to take away my freedom. they're an EPA tool, and when the EPA feels like it, they'll get rid of them too
The last Honda thumper I owned had a problem with rocker pads pitting/disintegrating. I dunno if that is better or worse than the cam pitting I had on a Honda twin and a Honda four. But I think I've had my last Honda. Nice paint. Nice plastic. Crappy metal underneath where it counts. I think it must be a Honda tradition that they are too proud to change. They hate copying other manufacturers--others create solid engines, Honda will have none of that. And I knew this guy that loved his XR600, heaped praise on it for its reliability. Then when he had it at his dealer, the dealer informed it needed $1800 of engine work. Boy, he was surprised.
If you like 2-strokes, it's your right and opinion. You can be vomiting from 4-strokes, it's your own problem. But I don't like 2-stroke-smokers, they eat more than twice a fuel of the same-capacity 4-stroke and more of double-capacity 4-stroke, they produce less than twice a power of 4-stroke, they don't have engine breaking which counts a lot on the road, they don't have linear power delivery, they break down a lot and take a lot of care to keep intact (take RGV250 for instance), they pollute, and they are hard to ride for novices. And as I see, 4-strokes are very competitive even as dirtbikes, not mentioning that they drove 2-strokes off the street. So hate 4-strokes as much as you like, don't dislike me for riding one..