Yz 450 fork conversion

Will the newer years (06'-08') yz forks and or triple clamps and stem fit on a 04' yz 450 ? I was interested in converting my 04' to the newer Kayabas, if anyone has information on this, please share. Thanks.

You would have to go with the triple clamps as well because the forks are larger in diameter.

Have you checked the total price on such a move? The new forks are very nice, but I wind up getting them re-valved after a few months anyway.

I think you could get your forks done by a good shop and be just as happy for just a few hundred dollars. Pro-Action does my race teams front and rear suspension and made my old 2003 YZ250F feel just as good as the new SS forks. They were so good that I sent my 2006 YZ forks to be done when I felt they did not handle the sharp hits as well as my 2003 after trying every adjustment.

You would have to go with the triple clamps as well because the forks are larger in diameter.
Not true. The '04 fork diameters are the same as the '06-7 models. I am uncertain as to the length of the stem, but they use the same bearings. The '06 fork tubes are placed 2mm farther apart in the clamps than the '04-5 models, and the axle lugs were set inboard 1mm each to compensate for that so that the same wheels and spacers could be used on both forks. Thus, if using the new fork in an earlier clamp, you would need to either trim 1mm (.040") from the left (brake side) wheel spacer, and possibly tweak something in the caliper mount (although it should be able to deal with 1mm), or recenter the rim over the hub by pulling it 1mm to the left.

Used parts would be the only sensible way to do this, obviously. It may be more practical to have yours redone by someone who is really good with single chamber KYB's, like Enzo, or Pro Action, but you can put a lot of money in that fork and not get something better than a stock '06. In the end, the most practical approach is probably to do what I did and buy an '06 and be done with it.

honestly just buy a nice used 06.

theres nothing better than that "centralized mass"

Not true. The '04 fork diameters are the same as the '06-7 models.

I stand corrected. I had an '03 which were 46mm and thought the '04's were practically the same bike. I have an '06 and an '07 and still swear by the Pro-Action fork job being just as sweet as the new forks for very little cost. You are right that a trade in bikes to an '06 might be just as cost effective.

Yeah, the '04 was the first year for 48's.

Who's the KYB expert at Pro-Action?

I stand corrected. I had an '03 which were 46mm and thought the '04's were practically the same bike. I have an '06 and an '07 and still swear by the Pro-Action fork job being just as sweet as the new forks for very little cost. You are right that a trade in bikes to an '06 might be just as cost effective.

I was in the exact same boat as the poster, but with an 03 yzf and tryng to find 05 suspension. i couldnt get used 06 stuff, it was 2006. I rode an 06 yz250f and instantly put my bike on the block to sell.

not that the swap would be cost effective. but he would reap the benifit of having a newer bike. It turns better, has 5 gears, feels lighter, doesnt hold oil in the frame. and so on. also, a 04 is 4 years old, and while theres nothing wrong with a 4 year old bike. the bearings in the bike are 4 years old, the engine is 4 years old, the wheels are 4 years old. if ya get a good 06, then hes dealing with a newer bike, and newer components.

also, if he swaps the front suspension, you really need to do something with the rear to balance it all out. but i really think that unless he can find an 06 on ebay being parted out, then its gonna be the same amount of money to swap the forks as it is to buy a newer bike after yours is sold.

not telling him what to do. but go ride an 06, and keep in mind that its not just the suspension that makes the bike feel so good.

Thanks for all the comments. I would like to move up to the 06' bike , but at this point my 04' is real fresh with high quality parts and the only thing left to modify is the front forks. That is why i'm looking into the newer suspension. On Ebay I am keeping track of a set of 07' yz 250f forks, triple clamps, stem and bearings complete. Any ideas if that would fit? I thought i read somewhere that the stem length for that year was shortened and thus wouldn't transfer, but i'm not sure. So if I purchased that set i might have to press on a new stem and make sure the wheel spacers align correctly, but thats it right? Sounds doable? Thanks again.

The 250F stem is 12mm shorter in the '04 model. You could get an '06 450 stem (if that's the right length for yours) or possibly use yours, or just do the wheel adaptation.

BUT, remember the the shorter stem means the forks themselves are shorter, too, so it will be like pulling yours up 12mm if you run them flush.

And of course, the springs are wrong.

This guy handles my race team http://www.wmxtreme.com (includes a fleet of 26 bikes) and everyone is very satisfied:

Pro-Action of Delaware

Rees Firestone

92 South Dupont Hwy.

New Castle, DE 19720

Phone: 302-322-3808

Email: info@proactionde.com

Web: www.pro-action.com/

As a side note, Rees is not only a KYB expert, although we ran mostly Yamaha's (KYB's) for the last couple of years. My mechanic has worked with him for 10+ years.

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