Looking for an off road shim stack for yz450 forks


2 replies to this topic
  • 67baja

Posted July 31, 2009 - 07:23 AM

#1

Here is the deal with my 07 wr450. It now has 06 or 07 YZ 450 forks on it which perform way better than the original wr forks. I weigh 170-175 in street clothes, and have just started off road racing the MRAN races in Nevada which include sand, rocks, pea gravel, boulders, silt, etc -- just about every kind of terrain except dirt or grass. The problem with this bike is when I let off the throttle or touch the brakes, the front end dives and knifes around and tries (sometimes successfully) to throw me off. If I tighten my compression clickers to keep the front end up in the stroke, it helps but at the cost of plushness. This bike is also hard to lean over in a turn at first, but then practically falls on it's side. It has stock 07 yz fork springs (.48s I believe) in the front and completely stock wr shock. According to the Race Tech spring calculator, the stock springs should work great for me. Sag is at 4".

Does anyone have a good stack for a yz450 for offroad racing? I read on another thread that removing 2 31mm shims from the each fork and adding a 24 in the remaining 31s works well. I have not yet opened the forks to check the current shim stacks, but suspect they are stock.

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  • ben_suhard

Posted July 31, 2009 - 07:38 AM

#2

I'm reading through the different stuff available from Dave at Smart performance. A few others have recommended him. There's a link in his signature. I'm reading through this thread at the moment http://www.thumperta...ad.php?t=721193

  • grayracer513

Posted July 31, 2009 - 07:46 AM

#3

I have two suggestions for you.

First, call Dave Johnson at Smart Performance. If you are up to doing the job yourself, as you seem to be, Dave has a kit available for the KYB SSS fork that modifies the mid-valve, base valve, and ICS springs, along with revising the rebound stack. You can get this stuff from him along with his own oil for under $300, and have a set of forks that are at least equal to anything available. I use the setup in my '06, and I'm very impressed.

Be sure to make the point that it's a WR with YZ forks, and if you want to also re-do the shock, (I recommend it), be sure to point out that it's a WR unit, if in fact it still is.

The second recommendation is to visit the Suspension Forum here. There are a lot of good builders on that one. If you just want to shuffle some shims, someone probably has some info for you. One thing I can tell you for certain is that the fork rebound stack is way too aggressive as to its initial response, and this leads to harshness on light surface inconsistencies (washboard). You will likely find 4-6 base shims in that stack. Dave recommends reducing that to 2, or even 1 in some cases.

I do highly recommend going with the full kit from Smart Perf. though. Tell him I sent you.





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