08 450 vs 08 450 Turning Wars


12 replies to this topic
  • dmonach

Posted July 31, 2008 - 10:33 PM

#1

Here is a puzzling one:

A friend of mine and I recent bought two new 08 YZ 450F. We both have had our suspension done and as luck would have it, we ride similar and with similar wieght. So.... We went with stiffer springs and the appropriate valving. The really question is why does one turn so much better than the other one

The race sag is very similar
The fork tubes are very close in postion in the triple clamps
Both bike are virtually identical in set up

With the exception of tires and actual clicker settings.

One has the Bridgestone M403 front and M404 on the back and one is the stock front tire and stock rear tire.

What gives....... could it be a simple as tires?

Penny for everyones thoughts..:ride: .. joking ......have no money left after the bike and upgrades....

Thanks

  • intensem1rider

Posted August 01, 2008 - 03:35 AM

#2

Tires are the biggest improvement for steering, the stock front tires are junk on the 450's. Replace the front tire and you should be carving turns in no time.

  • racerxx276

Posted August 01, 2008 - 04:46 AM

#3

"The race sag is very similar
The fork tubes are very close in position in the triple clamps
Both bike are virtually identical in set up"

This just goes to show how sensitive they YZF is to set up. Unless the sag and forks are exactly the same they will turn differently. I ended up at 103 mm sag and the forks on the line. Turns very well...

  • Ga426owner

Posted August 01, 2008 - 05:07 AM

#4

The body position of both of you on each bike will make a huge difference also.....I find the stock seat is too deep in order to get my weight and @$$ up on the front of the seat/gas tank...to where the bike turns sharper
Caveats - sag must be correct...for each rider.
If you swap rides...the sag for you must be set on the other bike
Was the revalve identical for each bike?
Tires......Stock Dunlop 739s are terrible tires for any frontend bite or any moisture here in my MXterrain area

  • Wiz636

Posted August 01, 2008 - 05:30 AM

#5

What is the stocker front tire? My '08 came with the 742FA up front and I really like that tire. The 739 is garbage unless you are going to ride on the street.

But really until you have all the settings the same they will both corner differently

  • grayracer513

Posted August 01, 2008 - 05:40 AM

#6

I have two questions:

When you say one turns better, does that hold true with either rider aboard the same bike, or does one of you just turn better than the other?

The other is, do both bikes have the same bars, and in the same position?

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  • dmonach

Posted August 01, 2008 - 07:18 AM

#7

grayracer

Yes we swap rides and and test. It is clear that one really turns better (the one with stock tires). I do not know his numbers but I am confident my sag is set to 104mm. The same guy set both of our sags when we got the suspenstion back (different times, weeks apart). The bars are the same bend, we both have the same BRP 22mm top triple clamps and bar mounts and tanks. His bike (the better turning one) even has the stock seat. I however do have a SDG seat.

I read thread somewhere here last night that the sag on the Yamie should be between 95mm and 100mm. Going lower in the sag number will great improve the handling but be a detrement to the stablity. Would anyone agree?

I feel as though his bike is a more "sloppy" ride in the whoops, but seems to track a bit better right out of corners.

Perhaps it is just super "sensitive" to even being a couple of mm off.

Thought?

  • grayracer513

Posted August 01, 2008 - 07:31 AM

#8

The late YZ450 seems to be exceptionally sensitive to everything. IMO, this is a result of having the mass so well centralized, and I consider it a good thing, since you can make changes and actually see something result from it.

The question of 104 vs. 95mm on the rear sag is a simple matter of head angle. The YZF has a shallower angle than some, and is therefore notably more stable than those same others, but tends to push more because of it. Raising the rear and/or pulling the fork up will steepen the angle, and yes, there is some penalty for this in terms of stability, but not much, and the YZ has some to spare. It also seems to be that the '08 needs the steeper head angle less than the '06/'07 does.

The front tires may be all that's different, and you could trade wheels to see what that does. But your "sloppy" comment leads me to believe that it could also be a matter of suspension adjustment, which will affect cornering, too.

  • Justin89

Posted August 01, 2008 - 10:42 AM

#9

Do you have the SDG step seat? I had one on my 2006 and it actually made me turn worse becuase it was so hard and high...

  • dmonach

Posted August 01, 2008 - 11:54 AM

#10

Not SDG step seat .... just the OEM replacement gripper.

Grayracer - Thanks again for the comments. I am going to recheck the sag on both bikes and find the happy medium on both.

One more thought... how much could setting sag without your gear on really effect the handling performance. Say I was set to 100mm in Street clothes but when fully suited up went to a 107mm -110mm. How much effect would this scenario have.

  • grayracer513

Posted August 01, 2008 - 01:24 PM

#11

It might make quite a bit of difference on a YZF. It's hard to say. I know that 5mm between setting at 100 and setting at 95 does.

  • DaveJ

Posted August 01, 2008 - 02:20 PM

#12

Perhaps two different forks.

Check this out.

http://www.thumperta...ad.php?t=675898

  • grayracer513

Posted August 01, 2008 - 03:10 PM

#13

Perhaps two different forks.

Check this out.

http://www.thumperta...ad.php?t=675898

GM calls stuff like that "mid-year changes", or "vendor production variances". :ride: Who'dathunkit?





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