New Yz 450's. Why so hated?


27 replies to this topic
  • grayracer513

Posted February 23, 2013 - 08:54 AM

#21

Regarding the exhaust, Dave at MRD identified the problem in early '10 as being due to a reduction in diameter at the end of the stock muffler to reduce noise enough to pass tech. His testing showed that the OEM header was so close to optimum that it didn't merit the work involved with altering it, and feels that a good slip-on is as good a solution as 90+% would need. Test results have borne that out for the most part, and getting rid of that tip restriction fixes the lack of top end pull.

Something that Yamaha has done for at least 15 years that contributes to the whole stink bug thing is to put handlebars on the bike that are so low it's silly. Throw something on the bike with at least an 85mm rise and things will feel much better.

The thing with the chassis is this: The whole idea of slanting the cylinder back was to move as much weight as possible as close to the center of gravity as possible so as to make the bike more maneuverable. That concept is easily understood by imagining carrying a 16 foot folding ladder. It's no lighter folded up than it is extended, but isn't easier to maneuver? The concept does, however, have a snag:

Looking at the ladder again, say you have it unfolded and you're walking it through your patio and happen to bump into a full trash can. The can falls down, and the end of the ladder barely moves off its line. Now imagine that it's folded, so it's easier to swing around, but there's a 16 foot pole taped to it. The pole weighs almost nothing. This time when you hit the trash can, the can deflects the end of the pole, turning the whole ladder away, and remains standing.

Just as centralizing the mass makes it easier for the rider to move the bike around, it makes it easier for outside forces acting at the ends (wheels) to rotate the chassis around the CG as obstacles are struck by the wheels, and that creates a problem for the suspension engineers. Now, we have to build a suspension unit that will absorb a small object without transferring a lot of motion to the rider, even though the end of the bike is much easier to lift, and yet at the same time be capable of handling the entire weight of the bike by itself on a landing. Something of a challenge, IMO.

For the mass centralization concept to work, suspension is going to have to advance beyond its current level of refinement, maybe a quantum leap forward. But it will be interesting to see how it goes now that Yamaha is moving the 250F to this design. I rather favor the BMW/Husky layout in which the crankcase is shortened and moved back while the cylinder is laid down. That layout lowers the CG, but keeps the mass spread out farther longitudinally. Still, it's an interesting time, watching engineering groups trying to find a way out of the conventional to some higher next level of chassis design.

  • sean3239

Posted February 23, 2013 - 08:57 PM

#22

I bought a 10 because I have always loved the Yamaha reliability and of course was intrigued with the new design. The bike to me does have flaws. On entrance to turns it feelt sketchy to me. Narrowing down the settings such as sag, clicks on suspension and tires helped but it never fully went away. I did notice that one time i got frustrated with my entrance speed because of that and just went harder into it and it stuck better than what the feedback was and that continued but the feeling is hard to dismiss..so that is something to consider (it works better than it feels).

The other thing is that the shrouds are wider, you can say its only "this" much wider but the fact is it does feel wider. It may or may not bother you but to dismiss as though its not an issue is a little hasty. The jerk off idle is an issue in ruts and other areas but you can fix that with a little out of pocket extras.

Because of this I went out and bought a 11 CRF450 and to me it was a better bike in terms of how I rode it. However, the suspension is horrible compared to the Yamaha off the show room floor. Simple things like springs (stock Honda springs was too soft for my weight) didn't fix the issue and get it close to the Yamaha SSS which is so nice.

I still have both of them and I ride both but I find myself preferring the Honda. It feels more nimble to me and that makes a bit of difference (I ride mostly MX).

I'm looking forward to the 2014 if rumors are that frame and tank modifications are to occur. This may fix the feeling entering turns and wide feeling I mentioned above . I would love to go back to Yami full time!

  • Greg Pennsiltucky Lykens

Posted February 24, 2013 - 06:51 PM

#23

I currently have both Ohlins TTX stuff and stock stuff on another couple bikes. The Ohlins makes it turn better, kinda like a Suzuki. I am not sure I would spend that money again at my age, as my lap times are only about .5 to 1 second faster on a consistent basis. For the money I spent, that 1 second could be gained on more riding and exercise. No joke. But it turns better. That comes from different people with Yamaha 450 bikes that rode my bike setup. Ohlins tells me it is the manufacturing of the fork and the tubes. I don't know, but it works. ( On a side note, the forks and shock weight 3 lbs, 7 ounces less than the stock components.Half that weight is unsprung. People spend loads on titanium to do that . Jut some FYI) . Also, Allesii runs the SAME forks and shock you can buy.



I am currently trying a stock shock modified. It is shortened 2 mm. So far I like it, the bike slides around bowls well, and it stays very level and neutral off jumps. Not a lot of flat corners though and I haven't ridden it back to back with my 2012 Olhins equipped bike......

One thing about this mod. I have only run it at two indoor parks over the last 3 weeks. So no real speed like outdoors yet. Maybe next weekend I can run outdoors.....


I have heard the same on the pipe, had Dave at MRD build one for my kids bike ( a 150R). Talked to him about these YZs, and told me that about all he could do is make a little more overun with the power. He advised me that since I don't run at 10 grand on the pipe, it probably wasn't for me. ( the guy is straight up with you) The bike makes over 55HP stock. How much do you really need? I usually get the holeshot, and I will tell you this, I run it with the ignition advanced and richer of idle to 1/3 throttle on the tuner. It lessens the bark, probably cuts down the power, but it is easy to handle. I figure that this is kinda what Kawi does with the little button on the 450, among other things. I am not in the pro level anymore, so good power is better than more. Probably for most others too.


Just a sidenote: My Ohlins bike is just for bigger MX races. I don't practice on it at all. The engine is the same, but the suspension is obviously different than my practice bikes.

I am about done with this thread. I really don't care if you like the Yamaha or not, I am just trying to give some of you some insite on this bike from a real riders point of view.

  • ah665

Posted February 25, 2013 - 09:50 AM

#24

I have read in a few threads that the 250F is getting the backwards motor, what is the source of that info (not to discredit grayracer or anyone else that mentioned it, because I put a lot of stock in what guys like him post)? I'm interested to see if not only can Yamaha build on this current design on their 450 or how they will transfer that over on the 250F.

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  • YHGEORGE

Posted February 25, 2013 - 01:50 PM

#25

Something must be coming with the 250 because the dealerships that are discounters have the current bikes VERY cheap now.

  • MxWhite260

Posted February 25, 2013 - 05:09 PM

#26

It's not as bad as the critics put it out to be. I am an A rider from IL, I follow a lot of the pro-am events and have used the yamaha yz450f since 2010. I hopped on the Kawasaki band wagon and got 2.8 hours out of a brand new (off the showroom floor) motor. Yes, it was a lemon but after that ill never buy a Kawasaki.

The reason people are skeptical to the yamaha is the handling. The shrouds are not as noticeable as people say, yes you can hear the airbox the first time you ride one but you will not notice after.

The only issue truly with the yamaha is that it's unpredictable (STOCK) you need to play with your fork height, your race sag and tire pressure. A lot of people ride the bike without giving it a chance, folks... It's not that bad!

Tons of power, especially if you throw a fmf exhaust on there and tune it to your specific wants.

Don't let the media persuade your thinking, be yourself, try things for yourself and you'll see how these bikes were exaggerated to be what they are not.

Ps.. You can still drag bars on these suckers haha

ImageUploadedByThumper Talk1361840960.068081.jpg




  • crf250r985

Posted March 03, 2013 - 12:29 PM

#27

It's not as bad as the critics put it out to be. I am an A rider from IL, I follow a lot of the pro-am events and have used the yamaha yz450f since 2010. I hopped on the Kawasaki band wagon and got 2.8 hours out of a brand new (off the showroom floor) motor. Yes, it was a lemon but after that ill never buy a Kawasaki.

The reason people are skeptical to the yamaha is the handling. The shrouds are not as noticeable as people say, yes you can hear the airbox the first time you ride one but you will not notice after.

The only issue truly with the yamaha is that it's unpredictable (STOCK) you need to play with your fork height, your race sag and tire pressure. A lot of people ride the bike without giving it a chance, folks... It's not that bad!

Tons of power, especially if you throw a fmf exhaust on there and tune it to your specific wants.

Don't let the media persuade your thinking, be yourself, try things for yourself and you'll see how these bikes were exaggerated to be what they are not.

Ps.. You can still drag bars on these suckers haha

ImageUploadedByThumper Talk1361840960.068081.jpg

thanks alot man! I'm a junior level rider in Canada and I am looking at a yz450f... Very helpful!

  • 2-Stix

Posted March 03, 2013 - 11:59 PM

#28

this bike is unreal. yes its jumpy in the rocks (trail rider only), throttle tamer fixed most of it with evs levers for a smother pull and richer settings with the tuner down low. i came off an 06 crf450, and i dont wash out the front end anymore, this bike sticks and hooks up and stays straight in the whoops. unreal bike.





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