Rear swingarm assembly

[nb1914]

Hi All,

I have ordered a new swing arm bolt and sleeve with brass bushes . I tried a dry assembly on the table and found that it appears as though the bolt won't fit in the sleeve potentially, i say potentially because I'm not sure how tight a fit this should be. The threaded end fits in upto the end of the thread, also the brass bushes are what would appear to be an interference fit on the outer sleeve. should all these parts fit together freely or is it required to put some force into it ? its possible that on the inner bolt that a lip has built up at the end of the thread that needs filing but just after some advice on how these parts should fit and whether its usual that some refinements are required.

 

[fredintoon]

Hi All,
I have ordered a new swing arm bolt and sleeve with brass bushes . I tried a dry assembly on the table and found that it appears as though the bolt won't fit in the sleeve potentially, i say potentially because I'm not sure how tight a fit this should be. The threaded end fits in upto the end of the thread, also the brass bushes are what would appear to be an interference fit on the outer sleeve. should all these parts fit together freely or is it required to put some force into it ? its possible that on the inner bolt that a lip has built up at the end of the thread that needs filing but just after some advice on how these parts should fit and whether its usual that some refinements are required.

Hi nb1914,
Didja buy new sealing washers too? (the existing ones are most likely too worn to re-use)
And an M16 threaded throughbolt & nut? (the M14 ended bolts can break the end off in service)
The bushings should be a light press fit in the swingarm.
Once in place I had to rent an adjustable hand reamer to open them up to be a nice slide fit on the bearing sleeve.
The correct fit-up has the bearing sleeve locked solid in the frame between the sealing washers with the throughbolt and nut torqued up properly.
The throughbolt should be a free fit inside the bearing sleeve. When correctly assembled the bearing sleeve and the throughbolt don't move at all.
The swingarm itself must move freely, with between 0.002" and 0.015" sideplay when the sleeve is locked in place.
My swingarm locked solid when the throughbolt was tightened because the bearing flanges were too thick.
I fixed that by filing across the bushings faces with a 14" fine tooth machinist's file.
And I'd advise putting a grease nipple in the swingarm crosspiece.
Grease fed through the throughbolt's grease nipples has a convoluted journey to get to where it's needed.

 

[nb1914]

Hi Fredintoon,

I bought the whole setup sleeve / m16 bolt with nylon nut / brass bushes / seals / and a couple of shims. So if i read correctly the bolt doesn't turn in the sleeve the swing arm rotates around the brass bushes. Looks like i need to dress down the bolt to get it into the sleeve.

Cheers
Andy

 

[fredintoon]

Hi Fredintoon,
I bought the whole setup sleeve / m16 bolt with nylon nut / brass bushes / seals / and a couple of shims. So if i read correctly the bolt doesn't turn in the sleeve the swing arm rotates around the brass bushes. Looks like i need to dress down the bolt to get it into the sleeve.
Cheers
Andy

Hi Andy,
the bushings should be bronze (copper+tin alloy) for it's excellent bearing properties not the less expensive and inferior brass (copper+zinc alloy).
And it looks like either your bearing sleeve is bored too small or your throughbolt is too fat.
The throughbolt should be a free fit through the bearing sleeve.
And yes, the bearing movement should be between a locked solid bearing sleeve's outer diameter and the bronze bushings' inner diameter.
IMHO the swingarm bearing's designer needed a stern talking to but absent a major re-design it's what we are stuck with.
Many reports of XS650's bad handling came from bikes with loose throughbolts letting the bearing sleeve turn with the swingarm so
that the actual bearing was the bad steel-on-steel fit between the throughbolt and the inside of the bearing sleeve which let the rear wheel wave about as it moved up and down.
So do it up tight, eh?

 

[nb1914]

thanks again, below is what i have, the brass bushes are and interference into the swingarm, the sleeve is interference into the bushes but loose through the swing arm, the bolt is close but free fit through the sleeve. looking at the bolt i think the issue is that where the thread stops its pushed out causing a slight lip so out with the file. the bushes are one of those things where once you start pushing them in theres no going back so is it best to stick em in the freezer.the shims i believe go on the inside of the seals not outside as i show here

 

[fredintoon]

thanks again, below is what i have, the brass bushes are and interference into the swingarm, the sleeve is interference into the bushes but loose through the swing arm, the bolt is close but free fit through the sleeve. looking at the bolt i think the issue is that where the thread stops its pushed out causing a slight lip so out with the file. the bushes are one of those things where once you start pushing them in theres no going back so is it best to stick em in the freezer.the shims i believe go on the inside of the seals not outside as i show here

Hi Andy,
The sleeve will FALL through the swingarm tube until the bushings are installed, eh?
The sleeve has to fit through the bushings AFTER they are pressed into the swingarm. The bushing bores tend to shrink a bit on installation.
I used the ol' deepfreeze trick on the bushings then forced them mostly into place using a length of 5/8" threaded rod, two big thick washers and two nuts as an assembly screwjack but I couldn't pull the bushings fully home with my wrenches. I had to drive them the last 1/8" in with a deadblow mallet. I didn't have an air impact wrench back then, perhaps that'd work to tighten the screwjack nuts enough to drive the bushings fully home and you wouldn't need to use a deadblow mallet. That or have longer wrenches and be bigger and stronger that me.
Then check if the sleeve slides in nice. Like I posted, I had to rent an adjustable reamer to open out the bushings after install to make the sleeve fit through them.
Someone else will have to say where the shims go, my swingarm didn't need them.

 

[nb1914]

Many thanks,

I filed the lip on the bolt and it now makes it through the sleeve ( it does not fall through but with some grease should be good ) the bushes i have in the deep freeze and will try to fit later in the swingarm. The sleeve also fits in the bushes again it doesnt fall through and as you say im sure once the bushes are installed the ID may be smaller so im expecting to have some additional dressing to perform.

 

[gggGary]

Make certain there is no paint in the end bores of the swing arm or on the ends where the bushing flange will stop. it would be good to hit those bores with some light sand paper then a solvent rag so you know they are clean. a stroke or two with a fine file so the ends are clean and flat... Some after market bushes are not accurately machined to size. I have one set of bushings that are so oversize they will NOT install. Lightly wipe parts with oil or maybe moly grease before attempting to install.
This thread covers shimming the assembly, takes a while to get to the meat but it's there. http://www.xs650.com/threads/swingarm-question.7607/#post-78537

 

[Michaelo]

The link to the thread was good Gaz, like your removal / install drift too very cool