Yz250 linkage slop

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11/20/2020 6:42 PM

So I know there are 20 threads on this but I can’t find any that show a fix for this. Linkage slop where the knuckle bolts to the swingarm. There’s a lot of slop right now. I can put brand new bearings in linkage and upper shock and it will get a little better but still not gone or close to gone. Is there a fix? Can I order a new knuckle and it fix it? I tried new bolts and it might have helped a little but not really. So now I’m wondering, is my linkage knuckle messed up or is it my Swingarm?

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11/21/2020 12:18 PM

Hard to guess without seeing your bike up close, but there's always a little bit of movement, maybe 1 to 2 millimeters of up and down at the rear wheel that won't go away. Or did you rebuild the linkage, upper / lower shock bearings but not the swingarm pivot that runs through the frame?

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11/21/2020 12:23 PM

silver753 wrote:

Hard to guess without seeing your bike up close, but there's always a little bit of movement, maybe 1 to 2 millimeters of up ...more

This is more than 1-2 mm. Every bearing in the bike has 31.5 hours on it. Except the linkage. I replaced them again and they probably have 15ish hours now. I am going to buy a new linkage knuckle and put new bearings in thag and see if that helps I guess. Kind of an expensive guess though.

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11/21/2020 2:30 PM

Take the knuckle to a good precision machine shop that can measure the bore of the knuckle and hardware and see if they are out of round. By the time you get to the axle, thousandths can seem like 1/8th inches.

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The older I get, the faster I was.

11/21/2020 9:31 PM
Edited Date/Time: 11/21/2020 9:34 PM

You can find bearings that are a correct press fit up until they get to the bearings actual landing / set point, so it is possible for that point to be flogged out.

You always should inspect the area that a bearing or seal is to sit in, for damage. Not everyone has things like internal bore measuring equipment, but a sensitive finger w00t , if it can reach the bearings set point, can be quite useful to pick up on a subtle change in bore - damage doesn't have to be visual to cause a loose, floating bearing. And, indeed, some bearings require the compressive action of a suitably tight bore / landing to give correct clearances.

If visual and 'feeling it' inspections don't give you a quick answer, capmoto's suggestion is far cheaper than buying a new knuckle.

As a basic, slightly sweeping rule, if the bearings go in with the correct press fit, all the way to their final setting, well, the knuckle bore or whatever bore they are sitting in is, generally, OK.

You can find plenty of bikes in the showroom with 'slop'. I find it (very) 'disappointing', but it's the sad reality of things, at times.

Genuine bearings are nearly always the best thing to use, by the way.

A few accessory brands bearings / bushings / pins / spacers and seals, really are dreadful things.

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