Swingarm adjustment side to side

[Rusty McNeil]

I can't remeber what thread this was discussed in so I'm starting a new one.

This pertains to using the same parts on both sides of the swingarm pivot to allow the swingarm to be adjusted back to the left and correcting the offset.



After replacing my broken driveshaft I found that the clearance around the u-joint looks to be plenty to allow movement back to the left without hitting the u-joint on the tube. It appears that the u-joint would make contact long before the driveshaft itself would were anything to make contact at all; which it probably wouldn't considering the amount of adjustement we are considering.

Not knowing this u-joint in particular but u-joints in general I don't think the the increased angle on the u-joint created by moving the swingarm to the left would be of much concern.

There IS something else I'm seeing that WOULD be a LOT of concern tho', at least for me....


The spline joint where the driveshaft inserts into the rear gear housing is where I'm seeing a problem being created....

Looking closely at the splines on the rear portion of the driveshaft it's pretty obvious that there is a "crown" in the middle of the splines and that there was some intent to create a "wobble" joint at this point.

My thinking is that this "wobble" joint is there to allow for SMALL inconsistencies and variances in driveshaft adjustment, u-joint wear, and perhaps frame and swingarm flexing.

My thinking is that it is NOT there to allow for a permanent 1-3??? degrees of angle to be thrown into it by moving the swingarm in relation to the output splines on the engine; and if this was done that the wear on these splines would greatly increase, perhaps not to the point of catastrophic and immediate failure but certainly greatly reduced life......


Any thoughts?????

Rusty

 

[one2dmax]

We've done this on a few bikes and it's even included in a kit for the swingarm otec sells. No issues yet and we push the bikes as hard as anyone ever will.

Sean

 

[maxcruiser]

Rusty,

I have had it on my 1st max for about 50000 miles with no issue and now on the new max with 11000miles - no issue.

It is primarily done to adjust alignment of the front to back wheel - it's common practice with bikes with chain drive - to be done at the rear axle assembly.

There's is about an adjustability of about 10-15mm either way.


Mike

 

[m-cman]

Is there a description on how to do this and what parts are needed? I have my swingarm apart for powdercoating and installing new bearings/seals, etc and will be installing a Kosman 18" wheel and Venture pumpkin also. Is this something worth doing in my situation?

 

[lankeeyankee]

The first time I removed my swingarm I counted the number of turns for each side when removing the bolts. I than marked both bolt heads the number of turns so I would remember when installing the swingarm.
I figured coming from the factory would be the most accurate in alignment.

I havent had any issues with it, and only broke one driveshaft due to a burn out on a concrete driveway.

 

[maxcruiser]

Ok here's the old thread that i originally posted the swingarm info on;

http://www.vmaxforum.net/showthread.php?p=32021#post32021

Mike

 

[gleno]

Just remember that drive shaft issues aside, a rear wheel offset can't be radically compensated for by moving the swingarm to far because you are also off-setting the incident angle of the rear shocks relative to the frame and the swingarm.

Make sure you compensate the shocks mounts accordingly or you are going to have some very unwelcome rear end dynamics.

 

[maxcruiser]

Just remember that drive shaft issues aside, a rear wheel offset can't be radically compensated for by moving the swingarm to far because you are also off-setting the incident angle of the rear shocks relative to the frame and the swingarm.

Make sure you compensate the shocks mounts accordingly or you are going to have some very unwelcome rear end dynamics.

Agreed Gleno, this may not be the solution to the wheel offset, but it is an easy way to align the front and back wheels. It is a way of improving the straight line tracking of the bike.


Mike

 

[gleno]

Agreed Gleno, this may not be the solution to the wheel offset, but it is an easy way to align the front and back wheels. It is a way of improving the straight line tracking of the bike.


Mike

Agreed. I used the same method to check my front back alignment. Works great. Just thought I had better let people know that If you change something on a bike sometimes you get unanticipated changes as well :thumbs up:

 

[Rusty McNeil]

Just remember that drive shaft issues aside, a rear wheel offset can't be radically compensated for by moving the swingarm to far because you are also off-setting the incident angle of the rear shocks relative to the frame and the swingarm.

Make sure you compensate the shocks mounts accordingly or you are going to have some very unwelcome rear end dynamics.

I'd thought of that too after my original post.

Thanks for all the replies guys, I'm still thinking about this one.

Is there any mechanical integrity/rigidity issues with swingarm mounting when doing this mod?

rusty

 

[gleno]

I'd thought of that too after my original post.

Thanks for all the replies guys, I'm still thinking about this one.

Is there any mechanical integrity/rigidity issues with swingarm mounting when doing this mod?

rusty

Yes there is. The further you move the swingarm bearing to one side or the other to compensate for a wheel offset, the less load bearing rigidity the pivot pin has. i.e. a bearing that is working nearer the frame will have more rigidity than one that is rotating around the end of the pivot pin. Same principle as using a lever. It's much easier to move the load with a lever if you hang off the end of it than it is to apply force close to the load.

 

[one2dmax]

though that is true you are still fully engaged with the swivel pins which themselves are very sturdy. You actually get closer to the frame section on the left side and farther away on the right.

This mod is one of the key mods when upgrading the handling of the bike. That along with solid mounts, dowel pinning the removable frame section, and switching out to radial wheels/tires makes the bike as good as it gets (not counting frame work).

Sean Morley

 

[Rusty McNeil]

though that is true you are still fully engaged with the swivel pins which themselves are very sturdy. You actually get closer to the frame section on the left side and farther away on the right.

This mod is one of the key mods when upgrading the handling of the bike. That along with solid mounts, dowel pinning the removable frame section, and switching out to radial wheels/tires makes the bike as good as it gets (not counting frame work).

Sean Morley

Thanks for the info Sean, i think the shock issue could be dealt with, was mostly wondering about the angle on the splines, but if you say y'all have ran them that long with no issue then apparently that wobble joint thingy is more tolerant of angle than I would have thought.

Short of frame work there not much else I could do to my bike now besides swingarm work and adjustment, which hasn't even been braced yet...

 

[m-cman]

Is there a "Sticky" or other source on this that gives detailed instructions and part numbers to do the mod?

 

[one2dmax]

Have you dowl pinned the removable frame section yet? Installed solid mounts AND frame braces? All those areas can be improved for someone wanting to get the most handling out of the chassis. I don't usually bother myself but not worried about the handling anyway.

Sean

 

[maleko89]

What do you mean by dowel pinned?

 

[Rusty McNeil]

Have you dowl pinned the removable frame section yet? Installed solid mounts AND frame braces? All those areas can be improved for someone wanting to get the most handling out of the chassis. I don't usually bother myself but not worried about the handling anyway.

Sean

Solid mounts
Frame braces
Fork brace
plus all the normal suspension stuff everyone does.

Haven't done the dowel pin thing. I had the frame section off when I did the motor mounts and it looked ot me like it had never moved so I didn't know if it was worth the trouble or not.
Is the point of the dowels to keep the mating surfaces from slipping around?

Or is it to stiffen the overall joint and prevent flexing?

Thanks,

Rusty

 

[one2dmax]

In short you replace the stock bolting system with a stud system that the frame section removes from and is drilled/tapped for a smaller bolt with washer to retain the frame in place.

This eliminates a flex area and firms up that last seciton of frame.

Sean Morley

 

[vmaxman99]

Sean, more info on this please! Any pics available?