Rear shock free play

Zesiger 112
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7/15/2015 3:43pm Edited Date/Time 7/17/2015 12:46pm
So when I have my bike on the stand I pull up on the back tire and it moves just a little then catches, then if I pull more I can feel the shock compress.
What could this be? Top shock bearing? I've replaced the bottom one so that's probably not it. Is it something to do with the linkage? Or even wear in the shock?
I have ridden with it like this and nothing feels wrong and nothing has broke. But I'm not going to just forget about it and have the shock go through the seat as I've seen others do.
I've tried to watch for shock movement but I can't really see anything move it's such a small amount
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mb
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7/15/2015 3:47pm
How much preload do you have on the spring?
Zesiger 112
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7/15/2015 4:05pm
What do you mean by that? The sag number? Or how far down the ring is?
Zesiger 112
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7/15/2015 4:07pm
It may also be the bearings in the linkage arm, because the bearings in the linkage have been replaced
racinstation
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7/15/2015 4:28pm
It is usually easy to tell. Have a buddy look at the bearings while you are lifting the rear wheel. I would bet that you have play in the lower shock mount bearing and/or the linkage bearings. If the linkage has just been replaced then look at the dog bones as well. It is a longer shot, but your wheel bearings could be suspect as well.

The Shop

karlz
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7/16/2015 2:22am
So when I have my bike on the stand I pull up on the back tire and it moves just a little then catches, then if...
So when I have my bike on the stand I pull up on the back tire and it moves just a little then catches, then if I pull more I can feel the shock compress.
What could this be? Top shock bearing? I've replaced the bottom one so that's probably not it. Is it something to do with the linkage? Or even wear in the shock?
I have ridden with it like this and nothing feels wrong and nothing has broke. But I'm not going to just forget about it and have the shock go through the seat as I've seen others do.
I've tried to watch for shock movement but I can't really see anything move it's such a small amount
If you find all the bearings are ok and you still get this feeling, you must check the shock. I have serviced shocks for over 20yrs and from time to time the nut on the end of the piston rod comes loose. If the shock is original and has never been rebuilt it needs sorting, but the case is more serious if it has been rebuilt. The reason for this is that the peening on the end of the rod has been removed and there is nothing to stop the nut coming off. The result of this could be a close encounter with a passing aeroplane.
ianhendry46
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7/16/2015 7:23am
My guess is the swingarm bearings. I have had many of my bikes do this and new swingarm bearings do it every time.
Bruce372
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7/16/2015 1:14pm
is it a showa? all showa shocks have a little amount of play in the top bearing.
Zesiger 112
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7/16/2015 1:24pm
It's an 05 yz125 so it's KYB. But not the good SSS KYB
Paw Paw 271
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7/17/2015 6:02am
There should be no free play anywhere in the rear suspension.

Paw Paw
1
slackinoff
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7/17/2015 6:50am
Although I have not experienced this. I have heard of guys replacing all the bearings and spacers and still have free play.

The bolts themselves can wear. I don't think that situation is common, but it is a possibility.
Paw Paw 271
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7/17/2015 9:36am
The bearings move on the bushings and not on the bolts. There are some aftermarket suppliers of these bearings and bushings that don't have them sized correctly and thus some free play is there and they is not right.

Paw Paw
holverson34
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Carlton, OR US
7/17/2015 9:44am
I've had 3 yzs and for some reason it seemed like they liked to go through more headset and wheel bearings than my other bikes.
b8res
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Lodi, CA US
7/17/2015 10:04am
I've had 3 yzs and for some reason it seemed like they liked to go through more headset and wheel bearings than my other bikes.
There is an updated headset bearing kits for the YZ's that offer better sealing. Local Yamaha dealer has the pn#.
slackinoff
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7/17/2015 11:23am
The bearings move on the bushings and not on the bolts. There are some aftermarket suppliers of these bearings and bushings that don't have them sized...
The bearings move on the bushings and not on the bolts. There are some aftermarket suppliers of these bearings and bushings that don't have them sized correctly and thus some free play is there and they is not right.

Paw Paw
Hey Paw Paw,

I agree on the aftermarket stuff being an issue with sizing. Last bike I did suspension link bearings, I used aftermarket and I could tell it was not made as well as the OEM I was pulling out. But whats your theory on the bolts??

How could an undersized bolt not cause free play? Is the theory that the torque on the bolts transfers that load to the bushings and thus the bearings?
Paw Paw 271
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7/17/2015 12:46pm
The bolts are only a way to hold all in place. None of the bushings nor bearings move on the bolts and if properly tightened they will hold the bushing in place for the bearings to ride on. There is one exception to this and that is the top shock bolt as the shock upper hiem joint does ride on it. In most cases the upper bearing wears out prior to any wear on the bolt , if properly tightened.

Many after market bearing kits, for the rear suspension, are of less that accurate sizing. I have tried to use some over the years and always end up going back to OEM parts. I have even seen several bushing missized in length and that will cause issues as well. All it takes is one miss sized busing or bearing and you will have slop and that creates accelerated were on all the others.

Paw Paw

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