09 yz450 swingarm swap yz250

3/22/2021 4:58am
I've read allot of posts about putting the 2009 yz450 swing arm on the yz250 two stroke. My question is what combination of linkage or dog bone people are using. Maybe the difference in different lengths and which performed best.
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mwssquad827
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Twin Falls, ID US
3/22/2021 3:49pm
We did a 09 250f to a 06 yz250 we used the 250f linkage and dogbone..
cdoggy81
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St. Petersburg, FL US
3/22/2021 10:06pm
Use the linkage that matches the swingarm.
09 yzf swingarm uses a 142mm linkage
A 143 or 143.5 is what a lot of the aftermarket likes as it drops the rear just a bit .
Your 06+ yz250 uses a 146mm so way to big.
1
3/23/2021 2:53am
cdoggy81 wrote:
Use the linkage that matches the swingarm. 09 yzf swingarm uses a 142mm linkage A 143 or 143.5 is what a lot of the aftermarket likes...
Use the linkage that matches the swingarm.
09 yzf swingarm uses a 142mm linkage
A 143 or 143.5 is what a lot of the aftermarket likes as it drops the rear just a bit .
Your 06+ yz250 uses a 146mm so way to big.
What is the triangular piece called? I'm guessing you use the one that was intended for whatever swingarm your using. Thanks for the help.
cdoggy81
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St. Petersburg, FL US
3/23/2021 5:23am
The knuckle & yes.
I haven’t been able to verify the exact mm differences between them but IIRC there are slight ones between the various models.
1

The Shop

3/23/2021 8:40am
Relay arm ( rocker / knuckle ) 17D-2217A-00-00 from 2009 to present is the same part number for all F (as of 2019).

For the YZ conversion the 143.5mm YPA10450 Pro Circuit pull arm sets the rear end very close to the stock YZ spec. There may be other companies that make a 143.5mm arm, but I'm not aware of them.

Pro Circuit says the YZ250F 2009 and 2014-2018 and YZ450F 2010-2020 is 142.0 mm and the stock YZ125/YZ250 2006-2021 is 145mm.




2
3/23/2021 5:29pm Edited Date/Time 3/24/2021 6:49am
Yeah, you're good. It's hard to measure. I even made some pointed centers to fit the links for improved measurement and still felt like I wasn't sure if I was within half a mm. I'm just quoting PC there.

Sort of like the F bar clamp centers. I've seen some say 102.5mm and others saying 103mm.

With the pull arms I measured the pivot to axle dimension and fender bolt to axle before I took the stock parts off. Then with the F parts installed I set the pivot to axle distance the same as it was with the stock parts. Then I started trying different arms and measuring the fender bolt hole to axle again. The OE arms made big differences to where the stock YZ was. It's like a couple of inches difference between the YZ and F arms. I tested both and did not like either one, even after moving the forks in the clamps to try and get the balance right. I'd say the YZ arm with the forks slid way up in the clamp is the better of the two options. The bike sits about an inch or a little more lower with that set up and the suspension still works good. Much like a longer 146mm or 146.5mm on a stock YZ. I messed around with that set up for a while. If you are short or want a REALLY planted feel in the turns, it's a viable option.

The 142mm F arm jacks the back end up about an inch and a half and apparently throws the linkage ratio way out of wack. It was way off and handled crazy to me. I can't imagine anyone liking that set up.

Then I got two adjustable Devol arms and that gave me a very wide range of adjustment and I played with a bunch of different settings and there was a 143.5mm setting. That got me right at the stock numbers for fender bolt to axle and I liked the suspension action the best with the shock valving I had. After riding with that for a while I was solid with it and found the PC arm was 143.5mm and just went with it.

So actually, you could go with the Devol arm, but I don't remember which one was the one that worked the best, but I was thinking it was the one for the 2008 and older F's. You'd have to contact Devol to get that info because they don't have specs for that arm on their website. They do the newer one and it doesn't have a 143.5 setting, so it must be the older one, but you'd have to verify that with them.

2
3/23/2021 6:13pm
Yeah, you're good. It's hard to measure. I even made some pointed centers to fit the links for improved measurement and still felt like I wasn't...
Yeah, you're good. It's hard to measure. I even made some pointed centers to fit the links for improved measurement and still felt like I wasn't sure if I was within half a mm. I'm just quoting PC there.

Sort of like the F bar clamp centers. I've seen some say 102.5mm and others saying 103mm.

With the pull arms I measured the pivot to axle dimension and fender bolt to axle before I took the stock parts off. Then with the F parts installed I set the pivot to axle distance the same as it was with the stock parts. Then I started trying different arms and measuring the fender bolt hole to axle again. The OE arms made big differences to where the stock YZ was. It's like a couple of inches difference between the YZ and F arms. I tested both and did not like either one, even after moving the forks in the clamps to try and get the balance right. I'd say the YZ arm with the forks slid way up in the clamp is the better of the two options. The bike sits about an inch or a little more lower with that set up and the suspension still works good. Much like a longer 146mm or 146.5mm on a stock YZ. I messed around with that set up for a while. If you are short or want a REALLY planted feel in the turns, it's a viable option.

The 142mm F arm jacks the back end up about an inch and a half and apparently throws the linkage ratio way out of wack. It was way off and handled crazy to me. I can't imagine anyone liking that set up.

Then I got two adjustable Devol arms and that gave me a very wide range of adjustment and I played with a bunch of different settings and there was a 143.5mm setting. That got me right at the stock numbers for fender bolt to axle and I liked the suspension action the best with the shock valving I had. After riding with that for a while I was solid with it and found the PC arm was 143.5mm and just went with it.

So actually, you could go with the Devol arm, but I don't remember which one was the one that worked the best, but I was thinking it was the one for the 2008 and older F's. You'd have to contact Devol to get that info because they don't have specs for that arm on their website. They do the newer one and it doesn't have a 143.5 setting, so it must be the older one, but you'd have to verify that with them.

Dang!! Thank you for all the info.
3/24/2021 4:57pm
I normally just say get the 143.5 link, so I thought I'd give a little more explanation as to why. I didn't document any of this, so it's from memory of something I did back in 2015. I also race XC, so if you are a moto guy you may like a slightly longer arm, but I doubt anyone would actually like anything shorter than 143mm. But, I've been wrong before.
3/26/2021 5:51am
I normally just say get the 143.5 link, so I thought I'd give a little more explanation as to why. I didn't document any of this...
I normally just say get the 143.5 link, so I thought I'd give a little more explanation as to why. I didn't document any of this, so it's from memory of something I did back in 2015. I also race XC, so if you are a moto guy you may like a slightly longer arm, but I doubt anyone would actually like anything shorter than 143mm. But, I've been wrong before.
I've found a bunch on thumper talk as well, but I also found the older posts you did with the devol linkage. You don't still happen to have that do you? Would like to be able to play around with different lengths and that one looks like the ticket.
3/26/2021 9:41am
You probably have more info than I can remember then. Laughing Did you happen to find the link part number?

Sorry, the link is long gone.

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