2005 YZF's valving

[ferg571]

Hey- can anyone out there help me? I have a buddy with 2005 YZF 250 and 450- if anyone knows the stock valving before I take it apart, could they send it to me? I would like to see where its at before disassembly, so he isn't down for an extended period of time. Or, if you know where I could go to get this info, send the link. I have already checked the Suspension Network, but it is very confusing- the columns show WAY more shims than what I have ever seen in forks; either that, or I am not reading it right. Somebody help! Thanks, guys!

[tasktm]

comp 24x0.1(11)

22x0.1

20x0.1

18x0.1

16x0.1

14x0.1

11x0.25

mid

16x0.1

22x0.1(3)

18x0.1

16x0.1

14x0.1

12x0.3

16x0.1

22x0.4

reb

21x0.1(6)

16x0.1

20x0.1

18x0.1

16x0.1

14x0.1

12x0.1

11x0.25

2005 250f/450f std valving

[bedell99]

Quick question did they keep the valving complete the same on both there 05 2 strokes and 4 strokes and just change springs and oil height.

Erik

[tasktm]

2 strokes have different set up ;clicker bleed has valving; more similar to showa setup,

24x0.1(9)

22x0.1

18x0.1

14x0.1

11x0.25

[ferg571]

Thanks, tasktm, but I am still confused?!?!?!? If I am correct, the mid you refer to is the midvalve. I am going to leave that alone. Why I am confused is that any other forks I have disassembled didn't have as many shims as you indicated- usually a stack for damping(same size shims), and then progressively smaller for a total of 10-15 shims or so. Could you explain further- and please bear with me, I am an amateur! Thanks again!

[tasktm]

yes ,there are 17 shims on the compression stack!

i would recomend you at least remove first shim (16x0.1)

from mid valve stack,and address internal cartridge pressure issues

by fitting 8mm spacer to ics spring ,machining chamfer on shaft on which

floating piston moves,55mm from valving end,to allow system to be purged

of air & excess oil,& drill a 4mm hole in plastic piston for formentioned reason.

The result will be worth the effort! it will allow you to make more informed

changes to compression settings! correct fork spring preload issues by fitting

longer springs of correct rate or fitting 7mm spacer under stock springs!

[floting]

thank you tasktm for this info, i have some questions. This chamfer, what is the shape and dimension. Where to install the spacer in IC., on the piston side or upper side? I read (dirtrider.net) that if you install the spacer for the fork spring on the down side it can be clipped by some internals on down moving , so it is advised to install it on the upper side, what do you think?

I have to do something with my forks because it is like blocking in the midstroke, so i suppose that this changes will solve the problem

Thank you!

[cmilktm]

I have to do something with my forks because it is like blocking in the midstroke, so i suppose that this changes will solve the problem

Thank you!

most of your problem to start is the fact that there is no preload on your main fork springs and the fork drops into the middle of the travel and beat you up.

Fix that first by adding a 7mm spacer or bying new aftermarket springs.

You do a spacer to the top for the ics chamber.

the spacer is to help with the bleed issue and most riders can get by with just that.

You can do the machining and drilling but depending n your riding ability I'm not sure you will ever notice the difference.

Once you tighten up eveything I think you will find your forks springs to be too stiff for your weight if you are 160lbs.

[bedell99]

I thougt the fork springs on the YZ250 2-stroke are spot on for a 150-170lb guy cmilktm. When I do decided to change the fork oil that the first thing I'm doing is adding some preload. I had some good results going in on the rebound 3 clicks and out on the compression 2 clicks. It funny once the forks broke in they where quite soft when breaking.

Erik

[floting]

Thank you for your answer!

I'm 190 lbs so i guess it will be just fine. In my understanding the chamfer and the hole in piston is helping to bleed out the trapped air and extra oil, so the ICS can perform correct and the shaft can move all the stroke. If this is correct than it is a must, or am i wrong and it can be done only with the spacer? i can bleed the chamber without this machining? Mop on DRN is describing a very interesting procedure to bleed out the trapped air without the need of machining something.

Sorry I'm still a little confused

[tasktm]

chamfer is there to allow for bleeding of cartridge, 30degrees taper ,

0.5-0.75mm deep 10-15mm long.

hole in piston is to give excess oil some where to vent,

personally i would fit fork preload spacer under spring,but it would have

to be of the design that it could not float sideways!

when fitted on top it can be struck by inner tube.

ics spacer on top of spring!

[cmilktm]

Where do you drill the hole in the piston?

[tasktm]

in the recessed area of plastic floating piston!

[yamaha259]

in the recessed area of plastic floating piston!

Any pics, you know pics are worth a thousand words. Thanks ?

[Nelson Carvalho]

hi,

I'm also revalving  my suspension AOS, I bought a suspension that already has a 5mm spacer on the base valve, not even cut evenly, I made new ones and installed them. Drilled 5mm holes on the base valve floating piston also.

I assemble the cartridge and it was incredible easy to bleed...fully compressed and then fully extended, without the spacer was not possible to have the rod fully extended. Not sure if this gives a faster rebound, which I don't like...