2009 YZ450 push


20 replies to this topic
  • Chop Shop

Posted November 23, 2009 - 09:54 AM

#1

Ok, its no secret that the 08-09 YZ450 has a tendency to push mid corner out. I had a pretty decent set up for loamy to hard tracks but cant seem to get the front end to stay down in a berm on sand..

What are people running for sag, fork height, tire or anything else that may help... The bike turns in, fine but as soon as you start to power through the corner the front tire begins to wander to the outside of the turn no matter how far forward you are on the bike. It was really annoying riding a sand track this weekend... I was able to carve better corners with my buddies KTM XCF... and that thing is a pig compared to the Yamaha!!

Thanks

  • The Italian Stallion

Posted November 23, 2009 - 12:12 PM

#2

Tall seat gets you in a way better position IMO.I felt a nice improvement when I moved the rear axle all the way to the back.I have my sag at 98 and my forks 12mm up some say this is too high but It works for me..I have 22mm clamps.Was it worth the expense?....not really.

  • Chop Shop

Posted November 24, 2009 - 06:58 AM

#3

Thanks. Im at 99mm and 6 up. 12mm up seems like a lot but I will try. Where are you compression and rebound? I ended up at 8 out instead of the stock 12 on the shock rebound. up front Comp 1 in from stock (11 i think)

  • saccityfire

Posted November 24, 2009 - 08:37 AM

#4

If your front and rear rebound are not close, you will be unbalanced and from your post you have the rear shock set to rebound faster than the front fork which will lead to the rear extending by mid corner which will bring the whole bike up and out in the turn. Even more important, I noted you ran this setting at a sand track. for sand you should be set very very stiff on compression damping front and rear.

On my 09 YZ450 I run 95mm sag with forks stock height and front and rear compression in 1 click from stock and rear high speed comp in 1/4 turn with front and rear rebound set stock. Handlebar mounts are all the way forward (+20mm) with stock bars. It does help to have axle towards rear of mount.

Additionally, I changed the tires to Dunlop Geomax MX 31/51 and will soon be 51/51.
further this bike is very sensitive to elbow position, keep em high! and make sure your head is over the bars.

The rougher the track and faster you ride the more comp damping you will need. My rebound stays pretty close to stock all the time.

  • MotoXT

Posted November 24, 2009 - 11:09 AM

#5

Tall seat gets you in a way better position IMO.I felt a nice improvement when I moved the rear axle all the way to the back.I have my sag at 98 and my forks 12mm up some say this is too high but It works for me..I have 22mm clamps.Was it worth the expense?....not really.


+1. Spot on. And, really focus on form. This bike requires it to be perfect to get it steer on par with others. Good news is it performs really well everywhere else. I've still got an '08, but picked up an '10KX, WOW, what a difference in the cornering department.

  • Chop Shop

Posted November 24, 2009 - 12:51 PM

#6

If your front and rear rebound are not close, you will be unbalanced and from your post you have the rear shock set to rebound faster than the front fork which will lead to the rear extending by mid corner which will bring the whole bike up and out in the turn. Even more important, I noted you ran this setting at a sand track. for sand you should be set very very stiff on compression damping front and rear.

On my 09 YZ450 I run 95mm sag with forks stock height and front and rear compression in 1 click from stock and rear high speed comp in 1/4 turn with front and rear rebound set stock. Handlebar mounts are all the way forward (+20mm) with stock bars. It does help to have axle towards rear of mount.

Additionally, I changed the tires to Dunlop Geomax MX 31/51 and will soon be 51/51.
further this bike is very sensitive to elbow position, keep em high! and make sure your head is over the bars.

The rougher the track and faster you ride the more comp damping you will need. My rebound stays pretty close to stock all the time.


I found that to get the rear to slow down its rebound and be more in tune with the front I ended up turning the rebound IN to 8 out... Not rebounding faster. There seems to be very little in the way of initial rebound with the valve stack, hence my position

  • l_campionero

Posted November 24, 2009 - 01:00 PM

#7

....What are people running for sag, fork height, tire or anything else that may help....


What is your weight, and what rate fork springs are you using?

  • grayracer513

Posted November 24, 2009 - 01:09 PM

#8

I found that to get the rear to slow down its rebound and be more in tune with the front I ended up turning the rebound IN to 8 out... Not rebounding faster. There seems to be very little in the way of initial rebound with the valve stack, hence my position

This is absolutely true of at least the '06 through '08 model YZ450. There is not nearly enough initial rebound response, and there's no cure for it other than to restack with additional and heavier shims. Dave Johnson recommended a base stack of 7 36x.30 and 5 36x.15 shims. All I can say is what a difference!

  • Chop Shop

Posted November 24, 2009 - 01:44 PM

#9

thanks for the stack Grey, I may pop her open and change it up.

  • saccityfire

Posted November 24, 2009 - 07:53 PM

#10

My 06 worked and 09 works very well stock after I changed the tire, handlebar position and fiddled with sag. I guess if you've never experienced a good cornering machine, you learn to live with what you've got. :smirk:

The HPSD steering damper I added has really added to the stability and my confidence in corners though.

I did have my 05 YZ 250 done by RG3 though and I like the stock 06 and 09 YZ450 better. Let us know how the new stack works...Perhaps I'm cheating myself! :excuseme:

:bonk:

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  • Chop Shop

Posted November 25, 2009 - 07:46 AM

#11

Will do... Like I said, I have a decent set up on the loamy tracks, its just the sand where I really felt the flaw in the front end. I had come off 4 consecutive Hondas, so I was surprised that the YZ was worse...lol It turns in better than the CRF, it just dosent give you confidence in holding your line.

  • grayracer513

Posted November 25, 2009 - 08:39 AM

#12

Sand is a problem, alright. Has many of the physical properties of a fluid, when you think about it, and behaves like one in many ways. To a degree, it's like riding on water.

I find in general that mine YZF's like to be leaned in a bit more than it gets when my body is aligned with the vertical center line of the bike, steering more with the lean angle than with the steering head. This, of course, puts a bigger premium on the tires, especially the rear, to hold at that increased angle.

  • YamaLink

Posted November 28, 2009 - 09:35 AM

#13

170 pounds without gear.
Rear sag at 90mm (disclaimer: have non-stock connecting rod on)
Forks raised 6mm from stock.

Front rebound: 5 clicks from full IN
Rear rebound: about 6 from full IN

I'm a pretty aggressive cornerer (didn't say "fast" but aggressive, ha). Butt crack finds its way home to the seat's edge, outside elbow up, inside grip pulled down, outside peg beat down, chin up, power never on-off. I like to turn a 450 with the rear wheel.

  • FinchFan194

Posted November 28, 2009 - 01:53 PM

#14

This is absolutely true of at least the '06 through '08 model YZ450. There is not nearly enough initial rebound response, and there's no cure for it other than to restack with additional and heavier shims. Dave Johnson recommended a base stack of 7 36x.30 and 5 36x.15 shims. All I can say is what a difference!


What all needs to be done to redo the base stack? I am about to spend a bunch of coin remodeling my house and don't have extra cash for my poor 08.

  • grayracer513

Posted November 28, 2009 - 03:12 PM

#15

Don't confuse the term "base stack" with a "base valve". The rear shock doesn't have one of the latter.

What I mean by that is that each valve stack has a set of shims that are the full diameter of the ported area of the piston. These are alternately called "base shims" or "face shims". In a rudimentary sense, this segment of the shim stack controls the amount of force required to open the valve at all, and therefore, how much "initial" damping the stack provides. In other words, it controls how much the valve damps slower velocity motion.

To change the shim stack, the shock has to be disassembled, the valve shims rearranged/added/subtracted, and reassembled. It's not a very difficult job, but does require A to B+ grade skills, the correct instructions, and close attention to detail.

Dave at SMART Performance will sell you a DIY kit with an instruction sheet if you believe it's something you can handle.

  • FinchFan194

Posted November 28, 2009 - 03:44 PM

#16

Great thanks for the info I will contact him here at TT.

  • saccityfire

Posted November 29, 2009 - 09:31 AM

#17

Gray, WHat does that Del taco kit cost?

  • grayracer513

Posted November 29, 2009 - 01:08 PM

#18

Not sure regarding the current cost. You should contact Dave for that.

  • psmith85

Posted November 29, 2009 - 09:03 PM

#19

I have 22mm clamps and they did not make that much difference. The 2 things that really helped me where a taller flat seat so I could get further up towards the front of the bike, and when I ditched the 756 front and Bridgestones up front and switched to the Michelin. I ride a track that some sand and other loose loamy dirt. The Michelin has made a lot of difference in how well the front sticks. It also turns better when the throttle is opened.

  • Wes Woodin

Posted December 19, 2009 - 12:29 AM

#20

I guess if you've never experienced a good cornering machine, you learn to live with what you've got.

this is true. when I had my 06, I thought it was the deal! I don't even want to ride a 2010 yet. It will make me want it.:moon:





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