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linkage bearing slop

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I know this has been discussed before, but I didn't want to resurrect an old thread. I have an 08 yz125 that has been a project bike to work on while I ride other bikes. The swing arm had play in it so I decided to change out the bearings. Lots of grease in these so they had been serviced before. The PO gave me an all balls linkage kit with the bike which was nice, and also a lower shock bearing kit. I ordered up an upper shock bearing kit. The all balls kit did not have all the correct size bearings which I found to be strange, I just cleaned up the 2 missing bearings they appeared to be in good shape with plenty of grease. The kit had all the sleeves, I have no explanation for that. After reassembly and torquing I still had slop but less than before. I ordered up a Yamaha swing arm bearing kit, and the missing bearings with Yamaha bearings and seals. Assembled it all and now slop is worse. Seems like there is too much clearance between the bolts and inner sleeve as I see the movement of the slop in the linkage mount to swing arm, and the L shaped linkage bolts.I estimate about 2 mm movement at rear wheel. Im thinking about removing the all balls stuff and just ordering all Yamaha parts.  Sleeve clearance to needle bearings seemed tight. Anyone else have this kind of issue? 

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Well I feel dumb. I think I forgot to put the washer on the bolt that goes through swing arm and relay arm. This would cause the nut to bottom out on threads and not tighten to the collar. Ill have to check when I get off work.

 

linkage snip.PNG

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I have had mixed results over the years with aftermarket and OEM bearings, but it does seem pretty common that there is still some play even when all the bearings are replaced.   I don't know that I have ever had one completely free of play.  If you think about it, in a linkage bike, even a tiny amount at each bearing point can add up to something measureable in mm when you add up all the bearings.  This is probably why my KTM PDS suspension is essentially free of detectable play when you grab the wheel after the upper and lower shock bearings are replaced.  There are a lot more bearings involved in a linkage bike.  

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49 minutes ago, rpt50 said:

I have had mixed results over the years with aftermarket and OEM bearings, but it does seem pretty common that there is still some play even when all the bearings are replaced.   I don't know that I have ever had one completely free of play.  If you think about it, in a linkage bike, even a tiny amount at each bearing point can add up to something measureable in mm when you add up all the bearings.  This is probably why my KTM PDS suspension is essentially free of detectable play when you grab the wheel after the upper and lower shock bearings are replaced.  There are a lot more bearings involved in a linkage bike.  

Thanks for the reply's. It was really bugging me cause I have an 05 125 with stock bearings and an 09 250f with stock bearings and zero play. This bike I picked up has been used way more use. I did get home and reassemble everything with the possible missing washer. put my son on the bike and torqued everything. There is a slight improvement but there still is just a bit of slop. The cumulative clearances due to many bearings makes sense. The sleeve to bolt clearance should be ruled out if all fasteners are torqued correctly .....right?

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I have a 2010 yz250 that I bought and had to replace all the rear end bearings in. Went with pro-x which is just a rebranded all balls. 

Bike probably got atleast 300+ hours on it before I bought it. Owner before me neglected maintence and probably powerwashed it often. 

Changed swing, linkage, upper n lower shock and I have zero play after I ridden it about 8hours. I changed the swingarm pivot bolt too, since the old one had seized badly and I can't stand rust.

Would probably try to change that bolt if I were you, can't tell you it's that bolt 100% but in my head it sounds resonable. 

Also make sure your torque wrench is calibrated. I've had alot of issues with bad wrenches before, usually leads to overtightening though. 

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 I am leaning towards theory of cumulative clearances in bearings. I just want to raise the question of the "what is the role of the bolt" within the discussion of slop in the linkage.  I was having a discussion with a friend who has wrenched on bikes and quads for years. He claims that the bolt to Collar clearance should not be the issue. The principle being once bolt is torqued the collar is compressed to the frame, linkage, or swing arm it should not play a factor in the slop equation. I am wanting to verify this theory with this community. I would really like to hear if anyone ever changed bolts and it made a difference.  

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Short of replacing the Swing-arm I've replaced everything OEM and aftermarket on our 2011 and still have a little slop . If I get the bikes back together(2011)-(2016) for a Holiday weekend . I'm going to switch the linkage then I will know for sure . 

Edited by Rosehill Ryder

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well this is just going to bug the crap out of me. 2.4 mm of free play measured with dial indicator at swing arm by rear axle.

 

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