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04 YZ250f forks HELP please

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Ok after a bit of testing I have some issues with my 04 YZ250f forks suprise suprise. I mainly ride enduros ie off road single track. The set up is fine as is bit harsh when going really slow over rocks but if I keep the pace up its fine.This is mainly hard pack riding. I'm running 2.5wt oil clickers comp about 12-16 out rebound 8 out Oil level is 20mm higher than stock.

My issue is when I ride M/X I ride on really rough sandy tracks the forks are unpredictable and crash through the stroke especilly when cornering after a set of major whoops. Its causeing the front to knife in. If I'm fresh I can catch it but if get tired as often I am at the end of a race I crash hard. Whats anoying me most is the upredictable nature of the fork. The shim stacks are below. Its all stock atm. On the sand tracks i'm running the comp at 6 out and the rebound on max. I can valve the rebound no probs but I've never played with a mid valve before.

The float on these mid valves is around 2mm huge compared to whats out there now. Also the mid valve face shim doesn't cover all the ports, its like its a bleed is this normal ??

So can anyone give me a starting point with the float on these forks and a heads up as to whats a good starting point with the mid valve. These are the wonderful cylinder valve forks its clean and the shims are ok.

What I want is a fork that reacts on the single track hard trails and will still be ok for sand M/X,am I asking too much?? I can deal with a little harshness on the trails but I'm 42 and would rather not if I can. I'm 80kgs run 0.43kg/mm at the front and a 5.0kg/mm rear. Any help would be greatly appreiciated This is really bothering me.

(DaveJ if you read this would one of your bush and mid kits help I don't want to go phase 4 I'd rather sell the bike and buy a 08 on)

Base Valve

Nut

Plate Spring retainer

Spring

Spacer shim

11x.25x1

Check plate side of piston

Comp side of piston

24x0.11x6

11x0.11x1

22x0.11x1

20x0.11x1

18x0.15x1

16x0.15x1

14x0.15x1

12x0.25x1

18x0.5x1

18x1x1

11x0.3x2

16x0.11x1

24x0.11x1

Bleed side of valve assembly

Mid valve

16x0.11x1

25x0.4x1

14x0.3x2

20x0.11x1

24x0.11x1

27x0.11x3

20x0.4x1

16x0.1x1

Piston

Rebound

27x0.1x8

12x.011x1

26x0.11x1

24x0.11x1

20x0.11x1

18x0.11x1

16x0.11x1

14x0.11x1

12x0.11x1

11x0.25x3

Thanks

Marty

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How bout just a float setting to start with the mid valve ??? Someone :)

MM

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I'm running 2.5wt oil clickers comp about 12-16 out rebound 8 out Oil level is 20mm higher than stock.

Marty, if you're running 20mm higher than stock, you're right at the minimum airchamber.

I usually try to avoid such high fillings.

Did you ever try a 5wt. oil?

I' against using 2.5wt oil in oc forks, but there are different opinions on this.

What I want is a fork that reacts on the single track hard trails and will still be ok for sand M/X,am I asking too much??

kind of :)

For sand you need (more) rebound.

Always bear in mind, when altering the rebound you're influencing the compression as well.

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i would like to help but i cant say i know how to make these forks work that well, i hate the mid design, i think it would be better as a rt style fork with a check plate, at least then it would be more consistant, i dont understand why it has the plate before the shim stack(25.4) the 16.1 mm shim is a bleed shim, these always make the fork feel a little unpredictable, trouble is if you run a normal stack on these forks the top shim distorts quickly,

the 11 cross over is a little small IMO, i would go with a 14, and less oil.get rid of the 16.1 bleed shim on the mid as well IMO, but i would just buy a tc fork from ebay and be done with it.

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Thanks fellas I'm going to go back to 5wt oil and try a few of your suggestions I'm going to close the float down to 0.8mm and see how it goes. Frenzo my idea with the 2.5wt was for the offroad stuff but it really in no good on the M/X track.

Mog I will try to get rid of the 16.1 but without the bleed I can see I may have to back off the base a bit this may help with the shim distortion! Have you tried this ?? I would love to get a TC fork off ebay but with the Ozzy dollar atm I'd rather buy a newer bike. I may have tracked down a 08 YZ250f cheap so if I can get it then all my issues will be solved:) :) No doubt I'll find some more on the new bike :banghead: :banghead:

Marty

ps thanks for the reply's

pps Anyone else ???

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the bleed shim is not helping much as with such a huge float its point is hard to work out?

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I don't undestand your question mog sorry :) I understand the bleed shim won't help, and understand the float issue. But "its point is hard to work out" I don't get. You mean you don't understand why it has a bleed and a huge float in the first place??

If so neither do I! They work fine offroad but on the track they are really bad stange as its a track orientated bike it is betterthan the 03 forks though they were unridable for me.

MM

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Thanks fellas I'm going to go back to 5wt oil and try a few of your suggestions I'm going to close the float down to 0.8mm and see how it goes.

0.8mm doesn't really sound like enough float. remember the big cartrige diameter means that there is a lot of oil flowing through the mid. that combined with the cv's tendancy to blow off cartidge pressure and cause the fork to blow through the travel means that you should probably be pretty conservative with the amount of float, unless you want to be replacing mv shims all the time.

I think I worked out one time that these forks flow about 30% more oil through the MV than 07-08 oc wp forks, and they seem to like about 1-1.2mm float, so as a guess 1.4 sounds a bit better. I have no testing to back this up however.

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I don't undestand your question mog sorry :) I understand the bleed shim won't help, and understand the float issue. But "its point is hard to work out" I don't get. You mean you don't understand why it has a bleed and a huge float in the first place??

If so neither do I! They work fine offroad but on the track they are really bad stange as its a track orientated bike it is betterthan the 03 forks though they were unridable for me.

MM

yes i dont see the need for a bleed shim and huge float.

you were saying if you remove the bleed shim you might need to go softer on the base, i was just saying that removing the bleed shim probably will only affect the rebound as it doesnt do anything on compression.

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Thanks will have to pull it apart this w/end and have another look have not had much to do with mid valves.

Dougie how do I firm up the mid then ?? Just shim shuffling I assuming. I will reduce the float and try a less aggresive amount of float :) Thanks. Just put both of my bikes on the market I want one with TC forks :banghead: I've found a cheap 08 so I hope all goes well.

MM

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