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Author Topic: 450R Swingarm  (Read 1536 times)

Offline Bsmith106

450R Swingarm
« on: November 29, 2020, 11:10:49 AM »
I recently installed an 04-05 length 450R swingarm on my 88 250R. The goal was to gain travel in droop and compression. The 250R setup bottomed out with roughly 3 inches frame height under the frame at the foot pegs. I wanted to get that to 1 1/2”. It extended to roughly 11” frame height before the wheels left the ground, so I had about 8” of travel(Honda specs it at 9.1”but they may measure the arc of travel and not vertical travel, not sure). After install I found the 450R swingarm hit the linkage mount on the frame at about 10.5” frame height. That’s not gonna work for my purposes. I considered scrapping it and going the no link route, but didn’t want to get into the expense and headache of moving or making a new airbox( I need an air box, woods riding). So I cut the frame linkage mount right behind the doubling plates the original bolt goes through. Drilled a new hole, centered in the remaining shorter linkage mount. This lets the swingarm swing down much farther than before. I wanted to use a long travel linkage. I settled on a Houser LT linkage designed for the oem 450R swingarm. Houser specs a 17” shock with 5” of shaft travel for this linkage on the 450R. (Side note:Houser says it’s for the 15mm longer 06+ swingarm. The 04-05 is 15mm shorter and the link mount is 15mm closer to the swingarm pivot bolt than the 06+. ). That didn’t matter as I wasn’t using 450R linkage locations on the frame. I had an unused shock from a DS450mx on the shelf 17 3/8 extended with 5” shaft travel. With the spring off the suspension will cycle to 2” frame height bottomed to just over 13” frame height extended(20”rear tires)With the springs back on and riding. It’s super plush but overall a bit soft, I will likely go up one spring rate or maybe go dual rate as the linkage ratio is pretty flat (not a lot of progression) very similar to a no link setup. There is a bit of rising rate, I have the numbers written down, just don’t have it handy at the moment.That’s where I’m at right now. Next move will be to shorten and re spring the shock to get to 1 1/2” frame height, I may remove the link mount and fab one in the 450r location (about 10mm down and 10mm back) Have to run the numbers and see what that would do to the progression. Its a backburner project that I have done when I have spare time. I believe a lone star linkage could be used with a modified 250R shock, needs 16.25 extended with 4.5” shaft travel. Stock 250R is 16” extended and 4” shaft travel. If the factory 06+ link was used it would probably need roughly a 15.5” shock. Not sure what stock 450R shock shaft travel is? For chain alignment I used 450R bearing carrier,brake stay, caliper, disk and disk hub. Used 250R axle,sprocket hub and wheel hubs. I’m still using the stock air box in the stock location.  I used a RJR 450r skid plate and Glann 450R chain slider.  Just figured I’d post this to possibly help someone out.

Offline 2ndmoto

Re: 450R Swingarm
« Reply #1 on: November 29, 2020, 03:23:04 PM »
Lots of good info. Share some pictures if you have time.

Offline Bsmith106

Re: 450R Swingarm
« Reply #2 on: November 30, 2020, 08:49:33 PM »
Here are a few photos

Offline Bsmith106

Re: 450R Swingarm
« Reply #3 on: November 30, 2020, 08:54:02 PM »
Few more

Offline 2ndmoto

Re: 450R Swingarm
« Reply #4 on: November 30, 2020, 09:22:25 PM »
That's a crazy looking linkage. Thanks for the post

Offline Langbolt

Re: 450R Swingarm
« Reply #5 on: December 02, 2020, 11:43:26 AM »
What did you do to get the Linkage to mate with the 250R Lower Link mount on the frame ?

Looks great..... Thanks for Sharing

:D


Offline Bsmith106

Re: 450R Swingarm
« Reply #6 on: December 05, 2020, 08:58:57 AM »
I cut about 1” off the link mount and drilled a new 10mm hole. Had to use some aluminum spacers to take up the gap between the 450r linkage and the 250r mount. keeps everything centered and allows proper torque on the bolt without stressing the link mount. The way it works out, I would bet other linkages for the 450R could be used and the shock length and shaft travel would be in the same wheelhouse as what a 450R would use with the same linkage setups. There’s so many 450R parts available new and used but in good shape. Won’t be able to use the 250R link anymore without fabbing a new link mount though. The frame would obviously still work with a no link swingarm.

 

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