07 first rides


10 replies to this topic
  • mxdad32

Posted February 27, 2007 - 10:16 AM

#1

Finally got the chance to ride my new bike. I had an 06 CRF450 last year and the YZ450f motor is way smoother. I love it. I am a top A vet in my area and was looking at droping down to a 250F with big bore kit but am glad I decided to try the YZF. The power is more like a 390 like one of the magazines said. The suspension is close but for me the front is a little soft. I bottom hard when slightly over-jumping in rythme sections and landing into the face of the next jump. I am about 175 without gear. Have any of you also found this top be true. I had the same problem with my CRF and went to .49 springs and 400cc oil volume. This is my first set of the new KYB forks and am not sure how it works with oil volume changes. I'm going to try adding 10cc and see what happens. I'm just looking for what others have done, andd yes I tried search several times but did not find and threads with answers from people at my weight and riding ability. Thanks in advance.

  • grayracer513

Posted February 27, 2007 - 10:28 AM

#2

The new Kayabas are similar in that they have a filled, sealed, and bled inner damper cartridge that is separated from the outer chamber oil volume. The outer volume oil has no damping function other than some of the bottoming resistance and, of course, the spring effect of the captive air mass above it, and is primarily a lubricant. They are a bit touchy about the outer oil volume. MXA took 10cc out to make the fork less harsh, and found they needed to put 5cc back. But try adding oil, nevertheless. You could also try a 5wt or a 7wt in the outer side only. Plan to completely dump at least the whole outer chamber oil charge unless you want to pay $27/qt for the OEM KYB fluid (Yamaha S1).

At your skill level, you may need to upgrade the stock suspension, as good as it is out of the box. Talk to a good suspension shop about springs.

  • Ranger18

Posted February 27, 2007 - 10:48 AM

#3

I weigh 185 and have not had a problem with the stock suspension, but you sound like your a lot better than I am. I would think a revalve would work rather than new springs.

  • Huckster

Posted February 27, 2007 - 10:50 AM

#4

I had mine revalved by FC. I am a bit heavier and slower than you, but they put in .48's and its awesome.

What were your inpressions of how it turns compared to the Honda?

  • grayracer513

Posted February 27, 2007 - 11:08 AM

#5

I weigh 185 and have not had a problem with the stock suspension, ...

I haven't either, but the situation he describes (landing against a jump face) is pretty severe, too.

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  • DaveJ

Posted February 27, 2007 - 01:28 PM

#6

Finally got the chance to ride my new bike. I had an 06 CRF450 last year and the YZ450f motor is way smoother. I love it. I am a top A vet in my area and was looking at droping down to a 250F with big bore kit but am glad I decided to try the YZF. The power is more like a 390 like one of the magazines said. The suspension is close but for me the front is a little soft. I bottom hard when slightly over-jumping in rythme sections and landing into the face of the next jump. I am about 175 without gear. Have any of you also found this top be true. I had the same problem with my CRF and went to .49 springs and 400cc oil volume. This is my first set of the new KYB forks and am not sure how it works with oil volume changes. I'm going to try adding 10cc and see what happens. I'm just looking for what others have done, andd yes I tried search several times but did not find and threads with answers from people at my weight and riding ability. Thanks in advance.



If the fork is sitting at a good height, statically, and in the corners, changing to stiffer springs or adding more oil in the lower chamber will help with bottoming, but will introduce a host of other problems. Stiffer springs are seldom the proper fix but people seem to do it. The guys at MXA are spring bias so be warned.

You're most likely bottoming because your stroke velocities are too high which means not enough compression damping, which in my opinion, is a problem with this bike. So are low speed pressure builds.

If you're feeling a hard bottom your oil locks (the lower camber) are most likely not operating at 100%.

The quick and easy fix? Change the oil in both chambers and dial in the compression damping. When oil breaks down in the lower chamber the oil locks don't perform as well. In the upper chamber it's a similar story but this is where all your compression damping is taking place.

By the way, with factory stacks, I found that one of the smoothest and fastest settings are 4 clicks out on the compression and nearly full out on the rebound.

Keep in mind that slow rebound rates are a big problem when it comes to maintaining control at fast speeds and certainly long whoop sections. In other words, if you packing the fork from the front portion of the whoop section, you’re going to bottom them at the back section, (not to mention how much this will slow your forward speed).

And too much low speed bleed is a sure thing for arm pump.

Change the oil, try these settings - you'll be surprised.

  • mxdad32

Posted February 28, 2007 - 04:46 AM

#7

Thanks for the replies. I rode the bike again last night and I have to say I like it even more. It feels way lighter than the CRF, even my sons CRF250. It turns very well compared to the Honda, I really haven't ridden it anywhere but on supercross tracks which were mostly 2nd gear but it experienced no push at all. On my CRF I had to put 22mm offset clamps to get it to turn. I came off of years of riding RM250 2stks and am pretty picky about turning and so far no complaints. This motor is so sweet, there is no arm riping excelearation which I think helps with the turning. This thing just hooks up and goes. I hated my CRF450 at Mototown which is where I have been doing almost all my riding this winter but the YZF is a dream. I am very happy I bought it instead of making a bigbore 250F.:lol: :cry: :applause: :applause:

  • Ranger18

Posted February 28, 2007 - 08:02 AM

#8

I haven't either, but the situation he describes (landing against a jump face) is pretty severe, too.


I guess I'm lucky to be slow. The farthest I make it is to the landing, with a few comming up shorts thrown in the mix. I don't know that my knee or back would appreciate me landing on the face of a jump:eek:

  • mxdad32

Posted February 28, 2007 - 08:08 AM

#9

At mototown some of the jumps have very little distance between them. In order to do one double/triple combo for instance you have to overjump the double just a little which puts your front wheel into the face of the next jump which helps you to make the following triple.

  • grayracer513

Posted February 28, 2007 - 10:16 AM

#10

I guess I'm lucky to be slow. The farthest I make it is to the landing, with a few comming up shorts thrown in the mix. I don't know that my knee or back would appreciate me landing on the face of a jump:eek:

It's like the conversation from Jody's Box:

Him: "Don't you think that 4th gear jump on the front straight is kind of dangerous?"

Me: "Not the way I do it, no" :applause:

  • Joe_Jet

Posted February 28, 2007 - 01:01 PM

#11

I'm 165 lbs no gear. I ride stricly MX at most of the tracks in SoCal. I went in 1 click on compression to 10 and raised the oil height 10cc to 350.

Also, as a side note, seals went bad after a muddy race at Glen Helen and tried the expensive Factory Connection double lipped seals and they only lasted 2 races, dry, no mud. The suspension shop that did the seals said he had another set of forks come throught there with the FC seals that also didn't last. I would stay awy from the FC seals.





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