All you guys sticking with Yamaha are using the same arguments you did when the raptor came out...its got more power...it has more bells and whistles...blahblahblah...Yamaha's don't hold up...this new one will NOT be an exception...I'll re-post this about halfway through the year and we can all re-evaluate our statements.

 

Is that right Ridley?

The Honda runs 11.5:1 - Yamaha 12.5:1

Both deliver similar peak numbers, the Yamaha "feels" faster because it lacks bottom end and has a 2 stroke like hit. The CRF develops power across a much better spread. A lot of this is because of it's excellent 21.5° valve angle & excellent flow characteristics.

What info do you have? You sure claim a lot of things & talk a lot of smack for a person that "leaves it at that" so often.

As far as sponsoring a factory rider goes -
I'd rather have two (or more) factory teams with sponsored riders competing out there with the factories fighting each other & upgrading the quads continuously to stay on top than a contingency program where the biggest money attracts amateur riders & the factories have less incentive to upgrade machines.

Dirtbikes get updated so often because of factory teams trying to stay on top, not contingencies.

Very few people get any REAL benefit from a contingency program and it spawns sandbaggers. If given only the option of contingency, I'd rather see them lower the price of the quad and have no contingency - benefits everyone.

 

Finally someone who understands the advantages of honda's "unicam" head. (1986atc250r)

I've noticed alot of people have been flamming the unicam design.

This is not a conventional rocker arm system. It uses lobes to open the intake valves. (just like the intake cam on the YFZ)
Then it uses a pair of rocker arms that ride on the exhuast lobes of the cam and open the exhuast valves. this set up actually has less friction and rotating mass than the YFZ's double overhead cam set up.

This cam set up was featured in many engineering magazines and journals when it was first let out of the bag in 2000. It is very cutting edge.

 

This probably at least partly explains why the CRF is able to have such a smooth power curve as aoopsed to the YZF.

I have spent time on both bikes and the YZF absolutely does NOT have more HP than the CRF, just different delivery. I also see all of the changes Honda made to the motor on the 450R as smart. Let's face it, there is a lot of difference in the way that a quad's power is distributed than a bike: two wheels as opposed to one, very different gearing, etc. I also think that an atv purchaser has different expectations on reliability and longevity which would also explain Honda's motivation for changing the motor around.

Personally, I don't dislike either bike (YZF or CRF) or either quad (YFZ or TRX450R). If I were to buy one today it would be the CRF mainly because of the power curve. It is just plays the 4 stroke advantages better than the YZF (The YZF is more prone to wheelspin than the CRF and it's not because of more power - it's how it's delivered).

MX

 

This cam set up was featured in many engineering magazines and journals when it was first let out of the bag in 2000. It is very cutting edge.

you have to be joking, this exact layout concept was used by triumph in the dolemite engine sport cars inthe late 1960 early 1970's,

disadvantages are that you cannot alter the cam timimg of just the intake or exhaust cause they are on one shaft, altering the exhaust or intake timing moves the power around nicely to suit conditions and is very standard practice on all DOHC race engines.

Rotating mass ! what a load of bull, direct valve actuation is light years ahead of any rocker arm setup regardless of it's fancy name ! if anything it is well accepted that any valve train configuration with rocker arms has way more rotating mass that has to be controlled by the valve springs ? they have done a half job (cam over intake rocker to exhaust) and convinced everyone it the way forward !

is honda reverting to a single cam layout on all there road race engines, No, what about there production road burners, no............ any other model where high HP is a criteria ?

1986atc250r: your missing the point, RELIABILITY issues, I hope honda has it sorted. I never said valve recesssion had any link to the engine lube problem, re read my post ? but Honda stated it was an "air filter maintenance" issue in their dealer bulletin ?. There is also a dealer bulletin on gearbox oil levels to combat early clutch plate burn out.

Engine failure due to lube problems, how does the 4 CRF's all losing there engines (all with rod lower end failures) at the same national event in NZ sound ! digging into the problem it looked like foaming of the engine oil due to heat / small volume ? maybe a wet sump setup is going to fix this ?

Anyways, it will be very interesting to see once they actually turn up in the real world. I had hoped for more from the Honda than what they have appeared to deliver ?

 

Everyone keeps saying they wanted more? What more did you want? An aluminum frame? Why? Because you can polish it?

<sheesh>

MX

 

you guy's are never happy,if they stepped out of the box on the design then you would have had something else to say about it,get a life and enjoy the new quad...

 

I was exspecting Honda to come out on their bike VTEC, like on the cars![img]i/expressions/face-icon-small-shocked.gif[/img]

Now wouldn't that be sweet.[img]i/expressions/face-icon-small-wink.gif[/img]

 

We are not talking about road racing here. This is the first time <u>This</u> specific set up was used in an off road mototrcyle.

And yes there is less rotating mass than in a dual cam setup, to see this setup used in a single cylinder off road motocross bike was cutting edge.

If you like i can post some links to the journals on monday, time to go drink beer. Work is finally over.

 

Lowbowtie,

they even have VTEC on their VFR800 street bike...

It's a 800cc V-Twin with V-Tec [img]i/expressions/face-icon-small-smile.gif[/img]..