2006 YZ450F - how to get this bike to corner?

The best thing I got for my 06 was $2500 so I could go buy a '10

You weigh 180# and run a .50 up front?? Damn...

I can easily machine in a new groove for the spring at work. I'll give that a try. 10mm is the magic number?

I think 15mm is what I settled at (haven't had the forks apart in over a year). I actually put the groove in 25mm up and made some 5mm spacers to stack on top of the seat.

You may want to check with Factory Connection. I think they make a spring seat for the '06 that has replacable spacers and doesn't require any machining.

Edited by 2grimjim

You weigh 180# and run a .50 up front?? Damn...

I can easily machine in a new groove for the spring at work. I'll give that a try. 10mm is the magic number?

It's SDI that has the spring seat and preload spacers. The spring seat as supplied has smaller bypass holes than the stock YZ but it can easily be modified with larger holes. I don't know if the SDI seat is any shorter than the stock seat but there is plentu of material if you want to shorten it and use their spacers to dial in the preload. Probably easier than machining your cartridge.

It's SDI that has the spring seat and preload spacers. The spring seat as supplied has smaller bypass holes than the stock YZ but it can easily be modified with larger holes. I don't know if the SDI seat is any shorter than the stock seat but there is plentu of material if you want to shorten it and use their spacers to dial in the preload. Probably easier than machining your cartridge.

Definitely easier for most people. I've been wanting to tinker with the front sag for a while now.

Dwight Rudder has this to say of off-road bikes in general:

"You can figure your correct sag numbers by using percentages. That way you can get the correct springs for you and your bike. Base these percentages on the available travel front and rear with a variance of + - 3 mm.

Front suspension static sag should be 14% ( available travel in mm X .14 = static sag in mm)

Front suspension rider sag should be 25% (X .25 = Rider sag)

Rear suspension static sag should be 11% of available travel (X .11 = static sag)

Rear suspension rider sag should be 34% of available travel (X .34 = rider sag)

Using these principles you can figure the correct sags for any bike and thus the correct springs without guessing and compromising."

How well that can be applied to an '06 YZ450 I don't know, but he seems pretty sure of it. I find that my static sag is about in this range, but the loaded sag isn't quite there. Forks are up in the clamps already. Also thought about a lighter spring rate with more oil. Everything else is working great, just this last area to work on.

Definitely easier for most people. I've been wanting to tinker with the front sag for a while now.

How well that can be applied to an '06 YZ450 I don't know, but he seems pretty sure of it. I find that my static sag is about in this range, but the loaded sag isn't quite there. Forks are up in the clamps already. Also thought about a lighter spring rate with more oil. Everything else is working great, just this last area to work on.

Try it. It's a fairly easy and painless mod. If you don't like it you can easily go back to stock preload. the difference is astonishing when you get it sorted out.

Rode again today with careful attention to the front fork action off the top. It's definitely got some excess preload on there.

Do you have the SDI part number? And yes, I feel a lot more comfortable turning down a small piece like that than the side of my cartridge, although it CAN be done. Will order tomorrow.

Rode again today with careful attention to the front fork action off the top. It's definitely got some excess preload on there.

Do you have the SDI part number? And yes, I feel a lot more comfortable turning down a small piece like that than the side of my cartridge, although it CAN be done. Will order tomorrow.

SDI has a PDF catalog you can download from their website.

Here's their website;

http://www.suspensiondirect.com/

Part numbers are;

Seat SDETCV24

2.5mm spacer SDEFSP025

5mm spacer SDEFSP05

10mm spacer SDEFSP10

Edited by 2grimjim

Do you have measurements for how much material you took off in length and how many spacers you needed? Putting together an SDI order and wondering if I need all these preload spacers.

Do you have measurements for how much material you took off in length and how many spacers you needed? Putting together an SDI order and wondering if I need all these preload spacers.

I couldn't tell you what to do with the SDI parts installed. I altered my preload before I was aware of the parts from SDI. The net result of the mods I did is I reduced the preload by 15mm. But I relocated the retainer ring 25mm and ended up with a 10mm spacer. None of this really applies if you are going to use the SDI seat. You will have to measure the seat length when it comes in and do your math from there. When you get your parts, please post the dimensions of the SDI spring seat here if you will.

$100 for a set of those seats....pass. At that point I'm actually better off relocating the circlip.

$100 for a set of those seats....pass. At that point I'm actually better off relocating the circlip.

That's $50 cheaper than the ones Factory Connection sells. Just do like I did then and put 1 groove 25mm higher up and make an assortment of spacers.

So I've got a test cartridge chucked up in the lathe ready to cut. How do you remove the preload collar from the cartridge? Just tap it downwards? I assume there's a circlip underneath it or something. I'm referring to the stop for the spring seat btw. It spins freely around the cartridge but is constrained up/down.

It should "snap" downward off of the retainer ring under it.

So I've got a test cartridge chucked up in the lathe ready to cut. How do you remove the preload collar from the cartridge? Just tap it downwards? I assume there's a circlip underneath it or something. I'm referring to the stop for the spring seat btw. It spins freely around the cartridge but is constrained up/down.

The steel ring has another ring captured under it. You have to cut the tapered end to expose the wire snap ring under it. Don't cut too much or you wil cut into the ring. Once you have the crimp cut off the major part of the steel ring can be removed. When I reassembled mine (on the new snapring groove) I just put the steel ring back on with some JB Weld to keep it in place. If you feel really motivated, you could make another steel backup ring and re-crimp it.

Make sure that you use a tool that makes a radiused groove the same size as the wire. I just used a parting tool and and ground a radiused end on it. You dont want to make a square-bottomed cut.

Edited by 2grimjim

So I've got a test cartridge chucked up in the lathe ready to cut. How do you remove the preload collar from the cartridge? Just tap it downwards? I assume there's a circlip underneath it or something. I'm referring to the stop for the spring seat btw. It spins freely around the cartridge but is constrained up/down.

You know, now that I think about it, you may not even have to make a cut for relocating the snapring.

Once you remove the steel backup ring, just leave it off. Originally, when I first did this, I was just going to make a long spacer that sat against the bottom of the cartridge (where the diameter changes). At the time, I didn't have enough aluminum tubing of the correct size to make two 4" long spacers. That's why I ended up relocating the groove.

Damn. I was hoping this would be some easily reversible modification. I may just look into using some shorter springs with some spacers behind the spring seat.

You know, now that I think about it, you may not even have to make a cut for relocating the snapring.

Once you remove the steel backup ring, just leave it off. Originally, when I first did this, I was just going to make a long spacer that sat against the bottom of the cartridge (where the diameter changes). At the time, I didn't have enough aluminum tubing of the correct size to make two 4" long spacers. That's why I ended up relocating the groove.

If I'm understandin' 2grimjim's last post correctly, this would be easy to reverse, ghill. Sounds like all a guy would have to do is remove the spring seat, and then make spacers for a spring seat on one end, and probably with an I.D. chamfer to seat on the tapering portion of the cartridge.....

JImmie

If I'm understandin' 2grimjim's last post correctly, this would be easy to reverse, ghill. Sounds like all a guy would have to do is remove the spring seat, and then make spacers for a spring seat on one end, and probably with an I.D. chamfer to seat on the tapering portion of the cartridge.....

JImmie

Exactly. The new spacer can be made any length you want, even if you want to keep or return to your stock preload.

After digging around my pile old suspension stuff, I found a set of old DRZ400 cartridge assemblies. The I.D. and O.D. are perfect size for making the spacer.....no machining required. Just cut the cartridge tubes to length and square the ends.

I have a set of '06 YZ forks I picked up for my YZ306WR project. I think that's how I'm going to alter the preload.

Edited by 2grimjim

The steel binder over the lock ring should not be omitted. It serves the dual purpose of giving the spring seat a better area to bear against, and it holds the retainer ring into its groove. Round wire rings subjected to axial loads need to be bolstered in some way as they have a tendency to be forced out of the groove under enough pressure. This is the same principal as the seal head or bladder cap on a KYB shock, or the ring that retains the steering stem. To counter this, either salvage and reuse the original ring by opening the crimp and forcing it down off the ring, or machine a new stop ring from steel having a step in the I.D. of one end that will slip over and hold the wire ring in place.

How do you suggest breaking the peen on this ring exactly? I was just going to skim it down on the lathe using either tape or glue to secure it rotationally and bring off a tiny bit of material at a time.

If I were to just machine off the peened part on the top to remove it and access the circlip, it SHOULD still function the same once the seat is loading it from the bottom, correct?

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