Side to side play on swingarm pivot?

[JNaw]

Hey all, question for ya.

A year ago I had some needle bearings installed in the rear swing arm as the old bushings were shot.

I'm doing some work on the bike right now and noticed the swing arm has about 1/4" of side to side play. Viewed/measured at the wheel axle end.

I assume this isn't normal? Is it just as simple as tighting down the pivot nut? I'm hoping they aren't shot again now, things barely had 1000km put on it since.

Edit: seems tightening the pivot nut got rid of the slop, will ensure it still moves freely. May not have been set correctly from shop or needed an adjustment after riding.

 

[Kevin Werner]

A 1/4" play is just fine when you are riding in a classic bike parade at 4 mph.

 

[GLJ]

Hey all, question for ya.

A year ago I had some needle bearings installed in the rear swing arm as the old bushings were shot.

I'm doing some work on the bike right now and noticed the swing arm has about 1/4" of side to side play.

I assume this isn't normal? Is it just as simple as tighting down the pivot nut? I'm hoping they aren't shot again now, things barely had 1000km put on it since.

Edit: seems tightening the pivot nut got rid of the slop, will ensure it still moves freely. May not have been set correctly from shop or needed an adjustment after riding.

1/4 inch to me is excessive. A better way is to make shims for each side and get it down to around .0010 inch. I'm not familiar with the needle bearing setups.
Trouble with pulling the frame together to get rid of the slop is you are distorting the frame.

 

[gggGary]

I installed one set of the all balls needle pivots, the second set will remain on the shelf. On a bike I was going to ride I'd want to know WHERE that 1/4 was coming from. and like GLJ if needed, shims, not reefing on the pivot nut, which also has been known to snap off the pivot shaft threaded end.

 

[JNaw]

I installed one set of the all balls needle pivots, the second set will remain on the shelf. On a bike I was going to ride I'd want to know WHERE that 1/4 was coming from. and like GLJ if needed, shims, not reefing on the pivot nut, which also has been known to snap off the pivot shaft threaded end.

Good point. I just find it odd it was fine when it left the shop and now it's worn in with a bit of slop.

I only turned the pivot nut about 1/2 a turn and she tightened up. Wonder if it was just parts settling in

From what I remember the shop didn't use the all balls kit, I can't remember the exact details, but supposedly was bullet proof.

Maybe I'll give the shop a call and see what they used, and may have to return it for workmanship warranty.

Thanks for the InSite guys. Whats the worst that can happen if it's over tightened?

 

[member43148]

I’m interpreting that “1/4” free play to be out on the end of the swingarm at the end of the axle adjusters hopefully ?
That would make more sense.

I believe bushings are the better choice over needle bearings for a swingarm pivot.

 

[JNaw]

I’m interpreting that “1/4” free play to be out on the end of the swingarm at the end of the axle adjusters hopefully ?
That would make more sense.

I believe bushings are the better choice over needle bearings for a swingarm pivot.

Yes that's correct. Sorry should've mentioned that.

I checked the torque on the nut. 47ft/lb was what I was reading, she's torqued to that and no more slop as well. Not too sure what would've happened to cause it to loosen up but either way it's all sorted.

 

[5twins]

For torque values, I like this chart from the '77 shop manual because they are given in ranges. I really feel you need that for things like the swingarm and the axles ......

Your 47 ft/lbs falls within the swingarm torque range (listed as "Pivot shaft and frame") so you should be fine.

 

[JNaw]

For torque values, I like this chart from the '77 shop manual because they are given in ranges. I really feel you need that for things like the swingarm and the axles ......

View attachment 326512

Your 47 ft/lbs falls within the swingarm torque range (listed as "Pivot shaft and frame") so you should be fine.

Yep that's what I was referring to when I said I was reading 47ft/lb (on the forums here). Set the wrench to that, got her snug and should be good to roll.

Thanks for the chart. I should screenshot mine off the Manual I have saved on my phone haha.

 

[5twins]

I start at the minimum and increase it a couple pounds at a time until the bare swingarm just gently falls under it's own weight.

 

[Its been a long time]

To echo what's been said. Stressing the frame by a 1/4" isn't really acceptable.

I actually don't like needle bearings on a pivot that only moves through a limited arc. I think bronze bushes are a better solution there, shimmed to (almost) eliminate the end float.

My thinking is that there should be zero detectable side float on the swing arm when it's tightened. But it should fall around the spindle under it's own weight.

Edited to add. Now I see that the 1/4" play is at the swingarm end. That really means the needle bearings or something else in there are now worn. Personally, I think I would want to know why there's a 1/4" play at the swing arm end. Just tightening the nut isn't really solving the problem, it's hiding it. My 2 cents is that in a few hundred miles the 1/4" free play will be there again.

Sorry that isn't what anyone wants to hear but that's my take on it.

 

[gggGary]

Some settling in of bearings is normal and God knows there's plenty of stock plastic bushings out there that have been flopping around for decades but....

 

[JNaw]

To echo what's been said. Stressing the frame by a 1/4" isn't really acceptable.

I actually don't like needle bearings on a pivot that only moves through a limited arc. I think bronze bushes are a better solution there, shimmed to (almost) eliminate the end float.

My thinking is that there should be zero detectable side float on the swing arm when it's tightened. But it should fall around the spindle under it's own weight.

Edited to add. Now I see that the 1/4" play is at the swingarm end. That really means the needle bearings or something else in there are now worn. Personally, I think I would want to know why there's a 1/4" play at the swing arm end. Just tightening the nut isn't really solving the problem, it's hiding it. My 2 cents is that in a few hundred miles the 1/4" free play will be there again.

Sorry that isn't what anyone wants to hear but that's my take on it.

I do agree that it isn't acceptable to have that Freeplay, but I'm still shocked they could've worn out that fast.

I noticed the locking tab on the nut wasn't fully set, so I'm wondering if it just loosened over time.

I will continue to monitor, as it's not a bike I ride out of the city. If it continues to wear out then I will take it apart and see what's up.

 

[Its been a long time]

I do agree that it isn't acceptable to have that Freeplay, but I'm still shocked they could've worn out that fast.

I noticed the locking tab on the nut wasn't fully set, so I'm wondering if it just loosened over time.

I will continue to monitor, as it's not a bike I ride out of the city. If it continues to wear out then I will take it apart and see what's up.

I think you need to look carefully to determine if the 6mm movement at the swing arm end is caused by -

Free sideways clearance at the swing arm pivot.

Or

Wear in the needle bearing assembly causing clearance between the swing arm, the bearings and the pivot shaft.

Either case is possible. Or a combination of both. How you fix the two conditions is different.

End float needs to be shimmed away. Wear in the bearing assembly means replacing whatever it is in there that's giving the excessive clearance.

I am not too surprised if you have premature wear in the needle bearings. Needle bearings are not ideal in a case where the rotation is a limited arc of movement. And the bearing surface that carries the load is a line contact. So lack of movement means poor lubricant effectiveness and the line contact in the bearing means relatively high localised loading in the bearing.

Myself, I would be thinking carefully about the root cause of the swing arm movement and take the appropriate steps to fix it.

Personally, in the case of an XS650 swing arm, I favour bronze bushes with a decent grease groove to ensure the grease gets to where you want it. Shimmed as required for minimum end clearance. That's much more suited to an assembly with a limited arc of movement and has lots of surface area to carry the load. Hope that helps.

 

[5twins]

I still have the original plastic bushings in both of my TX750 swingarms and they're fine, not worn at all. That's the beauty of most TX750 running gear - the bikes crapped out at such low mileages, the running gear is often still like new, lol.

 

[Its been a long time]

I still have the original plastic bushings in both of my TX750 swingarms and they're fine, not worn at all. That's the beauty of most TX750 running gear - the bikes crapped out at such low mileages, the running gear is often still like new, lol.

And there you go. Lots of surface area in the bush to carry the load and good self lubricating properties from the polymer. I would use plastic bushes ahead of needle rollers in a swing arm every time. Needle rollers there are a poor choice.

 

[JNaw]

I think you need to look carefully to determine if the 6mm movement at the swing arm end is caused by -

Free sideways clearance at the swing arm pivot.

Or

Wear in the needle bearing assembly causing clearance between the swing arm, the bearings and the pivot shaft.

Either case is possible. Or a combination of both. How you fix the two conditions is different.

End float needs to be shimmed away. Wear in the bearing assembly means replacing whatever it is in there that's giving the excessive clearance.

I am not too surprised if you have premature wear in the needle bearings. Needle bearings are not ideal in a case where the rotation is a limited arc of movement. And the bearing surface that carries the load is a line contact. So lack of movement means poor lubricant effectiveness and the line contact in the bearing means relatively high localised loading in the bearing.

Myself, I would be thinking carefully about the root cause of the swing arm movement and take the appropriate steps to fix it.

Personally, in the case of an XS650 swing arm, I favour bronze bushes with a decent grease groove to ensure the grease gets to where you want it. Shimmed as required for minimum end clearance. That's much more suited to an assembly with a limited arc of movement and has lots of surface area to carry the load. Hope that helps.

I checked the receipt for the parts installed by the shop and they are indeed the 28-1181 bearing kit.

I will look into swapping in either OEM bushings or bronze bushings if the Freeplay shows itself again. Or may just for the piece of mind.

Thanks guys.

 

[Its been a long time]

I checked the receipt for the parts installed by the shop and they are indeed the 28-181 bearing kit.

I will look into swapping in either OEM bushings or bronze bushings if the Freeplay shows itself again. Or may just for the piece of mind.

Thanks guys.

Good luck with it. My personal choice would be bronze bushes with a nice spiral grease groove. I would make them slightly under size in the bore so that after fitting them in the swing arm I could use an adjustable reamer to get the fit on the spindle perfect.

 

[JNaw]

Good luck with it. My personal choice would be bronze bushes with a nice spiral grease groove. I would make them slightly under size in the bore so that after fitting them in the swing arm I could use an adjustable reamer to get the fit on the spindle perfect.

I believe they sell kits with the bronze bushings? Unfortunately I don't have a lathe to make my own haha

 

[Its been a long time]

I believe they sell kits with the bronze bushings? Unfortunately I don't have a lathe to make my own haha

Indeed, yes. Others with more knowledge on that will advise. I'm certain you'll be far happier and safer on the bike without 6mm movement in the swingarm!