Need quick answer 99 YZ400 rear arm options

[kevin1209]

I have a 99 YZ400. Can I use the rear arm off an 01 YZ426, or an 03 YZ450? The part number for the 99 is 5CU-221100, the 01 is 5MV-221100, and the 03 is 5UN-221100. Are they different sizes, or just updated part numbers???

Please answer quickly, I need to get this thing bought so I can start riding!!!!!

[l_campionero]

I believe there are differences in the linkage attachment points.

[grayracer513]

In the first place, your part numbers are wrong; a swing arm is a *-22110-*-*, not a 221100. The similarity in the basic number means only that they are all swing arms. A 5HN-22110-00-00 is also a very similar number, you'll notice, but it's for a TT-R 90.

There are multiple differences in the swing arms you mention, and some interchangeability does exist. I believe an '01 YZ426 will fit, but you should either search or wait for a more definitive answer.

[kevin1209]

I just bought one that came off a '01 YZ426. It was only $60 shipped (used of course), so I wanted to get it before someone else bought it. I think I'm OK, they didn't change the shaft diameter until 02, so hopefully it fits. Both of my chain puller bolts seized up and snapped off, despite PB lube and gentle handling. Then I proceeded to break off an EZ out in one of them while trying to remove the broken bolt. This was after having to replace the worn out AP diaphragm that caused a gas leak. This $1,000 deal is quickly making me mental!!!!! Being broke sucks!

[myoung]

The '99 swingarm and '00 swingarm sitting in my garage look identical. The changes to the swingarm and linkage were in '02, but the '02 and later swingarm will work. My guess is the '01 will be the same.

[Birdy426]

01 and 02 are a bit different. The linkage is the same, but the attachment of the rocker link to the swing arm uses a flat spot on the bolt head to keep the bolt from rotating rather than a hex bolt. The swing arm pivot bearings are different as well. I think the 02 had a larger pivot bolt so it takes a mix of parts from 01 and 02 to get a bearing set up that works. It's been a while, but I know I needed parts from both kits to make the 02 arm work on my 01... I'm not sure, but I think the 400's had a bit smaller axles than the 426's...have to check the part numbers...

[myoung]

01 and 02 are a bit different. The linkage is the same, but the attachment of the rocker link to the swing arm uses a flat spot on the bolt head to keep the bolt from rotating rather than a hex bolt. The swing arm pivot bearings are different as well. I think the 02 had a larger pivot bolt so it takes a mix of parts from 01 and 02 to get a bearing set up that works. It's been a while, but I know I needed parts from both kits to make the 02 arm work on my 01... I'm not sure, but I think the 400's had a bit smaller axles than the 426's...have to check the part numbers...

Yeah, it's a bit of a hodge podge using the later stuff. I put an '05 on my '00. I couldn't use any of the '05 linkage but had to use the '05 relay arm pivot bolt and had to use the '00 pivot bearing sleeves for the smaller '00 pivot bolt.

My guess is '98 to '01 are dimensionally the same and '02 to '04 are dimensionally the same, '05 maybe dimesionally same as '02-04, but might be totally different if you're saying the '01 and '02 linkage was the same. I know there were changes to '05 for weight which could also explain the different part #'s. That's mostly why I used '05 on my '00. Either way, looks like the pivot bolt didn't change till '02 and '99-'01 is all interchangeable.

According to an oem parts fiche site, #'s for steel frame YZF's are;

Swingarm #'s.......'98, diff.......'99-'01, same......'02, diff......'03-'04, same......'05, diff

Pivot bolt #'s.......'98-'01, same........'02-'04, same.......'05, diff

Relay arm #'s.......'98, diff......'99-'01, same......'02-'04, same.....'05, diff

Connecting rod #'s.......'98-'01, same.......'02-'03, same, '04, '05 both different.

[grayracer513]

With regard only to the axle question that was just raised, the '98 YZ400 has a 20mm rear axle, all models '99-'08 use a 22mm rear axle, so it's not an issue in this case.

[Birdy426]

With regard only to the axle question that was just raised, the '98 YZ400 has a 20mm rear axle, all models '99-'08 use a 22mm rear axle, so it's not an issue in this case.

Thanks, Gray, I thought there was a difference somewhere, but couldn't remember the details...