Swing arm adjustment

Message

spiderwheels · #1 Post by **spiderwheels** » Thu Dec 29, 2016 11:46 am

In the Falco service manual (section 2.30) there is mention of adjusting the rear fork if there is any slack.

It gives a torque figure of 12Nm for the adjuster bolt.

When I swapped my swing-arm for the one I got off Keith I did the bolt up to 12Nm but found there was still free play. So I 'adjusted' it further to the point where I couldn't feel any free play and the arm still moved freely up and down.

I've just done the same with my girlfriend's SV. Taking it to 15Nm as specified in the manual left it with play so I carefully did it up tighter until there was no free play but the arm still moves easily. It was around an extra 1/4 turn.

I don't know if this was the right thing to do in either case. I find it contradictory that the Falco service manual calls it an 'adjuster' and specifies an exact torque - to my mind adjustment is a process of gradual feedback as opposed to tightening something up to a given torque.

Have I done the right thing or do both bikes need new bearings?

fatboy · #2 Post by **fatboy** » Thu Dec 29, 2016 6:54 pm

This is unexplored territory to me having never had to mess with bearings ( only bushes )
Two thoughts spring to mind...
Can you verify the accuracy of your torque wrench as we are dealing with very small increments ( did you set the wrench on a lower setting and gradually work up to the setting ect. ?)
If what you have done works and remains workable with no noticeable play returning in a short time then what you have done works, the figures are ball park figures.
As you say the Falc describes 'an adjuster' so if it is adjustable then how can you have a fixed figure for that ?

blinkey501 · #3 Post by **blinkey501** » Fri Dec 30, 2016 9:28 am

Are you talking about the adjuster that fastens the swingarm to the frame?
Or the adjusters that tension the chain?

spiderwheels · #4 Post by **spiderwheels** » Fri Dec 30, 2016 12:07 pm

fatboy wrote:As you say the Falc describes 'an adjuster' so if it is adjustable then how can you have a fixed figure for that ?

Granted my torque wrenches may not be the most accurate things in the world although nothing breaks / falls off / or is stripped of threads when I use them.

I've been trying to find out how an axial load (i.e. a force along the direction of the swingarm pivot bolt) can make any difference to a couple of needle roller bearings in the first place.

Like you say though, if it works...

blinkey501 wrote:Are you talking about the adjuster that fastens the swingarm to the frame?
Or the adjusters that tension the chain?

The swingarm to the frame. Even I wouldn't try taking the play out of the swingarm with the chain adjusters and that's saying something!

fatboy · #5 Post by **fatboy** » Fri Dec 30, 2016 7:11 pm

Any type of bearing, be it ball,needle, roller or bush works best within specified clearance limits.
When those limits are exceeded then the load transfers from axial to torsional, you now have side to side play.
If you were to put a pencil in a snug fitting tube and leave a small amount protruding from the end it will be difficult to snap the pencil,put the same pencil in a larger tube and its easy to snap ect.
Even a regrease can give bearings an extended life, hope it works !

Gio · #6 Post by **Gio** » Fri Dec 30, 2016 11:13 pm

I've know it where a set of ball races were crushed oval with to much tightening

blinkey501 · #7 Post by **blinkey501** » Sat Dec 31, 2016 12:08 am

spiderwheels wrote:
fatboy wrote:As you say the Falc describes 'an adjuster' so if it is adjustable then how can you have a fixed figure for that ?
Granted my torque wrenches may not be the most accurate things in the world although nothing breaks / falls off / or is stripped of threads when I use them.

I've been trying to find out how an axial load (i.e. a force along the direction of the swingarm pivot bolt) can make any difference to a couple of needle roller bearings in the first place.

Like you say though, if it works...

blinkey501 wrote:Are you talking about the adjuster that fastens the swingarm to the frame?
Or the adjusters that tension the chain?
The swingarm to the frame. Even I wouldn't try taking the play out of the swingarm with the chain adjusters and that's saying something!

Hi mate.

Not all have mechanical skills, and I wanted to establish what you was talking about.

If you have mechanical skill, then ditch the torque wrench, and turn the adjuster against the bearing with the allen key in the axle pin..

Keep moving the swingarm side to side, and the axle pin with the adjuster until there is no side ways movement.

There needs to be just enough pressure on the side of the bearing to prevent movement, before locking the adjuster off with the castle nut.

spiderwheels · #8 Post by **spiderwheels** » Sat Dec 31, 2016 6:22 pm

fatboy wrote:Any type of bearing, be it ball,needle, roller or bush works best within specified clearance limits.
When those limits are exceeded then the load transfers from axial to torsional, you now have side to side play.

OK, makes sense ta!

Gio wrote:I've know it where a set of ball races were crushed oval with to much tightening

I don't think they've been crushed. The arm still moves freely and smoothly.

blinkey501 wrote: If you have mechanical skill, then ditch the torque wrench, and turn the adjuster against the bearing with the allen key in the axle pin..

Keep moving the swingarm side to side, and the axle pin with the adjuster until there is no side ways movement.

There needs to be just enough pressure on the side of the bearing to prevent movement, before locking the adjuster off with the castle nut.

That's exactly what I did before I posted this thread. I was just trying to ascertain if it was a bad idea or not.

blinkey501 · #9 Post by **blinkey501** » Sat Dec 31, 2016 9:27 pm

spiderwheels wrote:
fatboy wrote:Any type of bearing, be it ball,needle, roller or bush works best within specified clearance limits.
When those limits are exceeded then the load transfers from axial to torsional, you now have side to side play.
OK, makes sense ta!

Gio wrote:I've know it where a set of ball races were crushed oval with to much tightening
I don't think they've been crushed. The arm still moves freely and smoothly.

blinkey501 wrote: If you have mechanical skill, then ditch the torque wrench, and turn the adjuster against the bearing with the allen key in the axle pin..

Keep moving the swingarm side to side, and the axle pin with the adjuster until there is no side ways movement.

There needs to be just enough pressure on the side of the bearing to prevent movement, before locking the adjuster off with the castle nut.
That's exactly what I did before I posted this thread. I was just trying to ascertain if it was a bad idea or not.

No it's fine.
I have done 3 now with no issues.

spiderwheels · #10 Post by **spiderwheels** » Sun Jan 08, 2017 4:35 pm

blinkey501 wrote:
No it's fine.
I have done 3 now with no issues.

Thanks very much