Is there a difference between rear swing arms?

[Yahman]

Can someone tell me if there is any difference between the rear swing arm an XJ1100 and the XS1100’s?

Thanks,
Larry

[TopCatGr58]

Hey Yahman,

THey take the same bearings, and you can swap the "swirly" rear wheels from XJ's onto XS11's, so even though they are listed as a 10M series Yam. Part # for the XJ vs. the 2H7 # for the XS's, I would think they would be the same...perhaps the only difference being the type of paint used, as well as the size/spacing of the rear shock mount....since the XJ had the fancy air adjustable vs. the XS's regular style...but not sure about that!?
T.C.

[Yahman]

T.C.

Thanks for the input, that's what I had concluded from my research. So now onto the reason I asked the question. Why do you think the rear wheel is offset to the left side like this?

[IMG][/IMG]

I have checked the alignment with a laser and I determined that it's off to the left by exactly 0.5 inches. The rear is strait with the front, everything seems to be square, it's just off to the left side. I can't find any sign of damage to the front end, the frame or the rear end. I was going to check it again using the method at this link, just to confirm my findings.

http://www.motorcycle.com/how-to/chassis-alignment-basics-3444.html

After that I was going to take the rear end and suspension apart for a more thorough examination.

Any thoughts on this mystery would be much appreciated.

Thanks,
Larry

[bikerphil]

adjustment

If the wheel is vertically level with the bike itself, but is just over to the left 1/2 inch, that can be adjusted. Pop the chrome caps off the frame (left and right) where the swingarm bearings are and the adjustment is under there. Do you have a service manual? It will tell you how to adjust this.

[xschop]

ouch

Your right shock is jacked to the left by that much as well....Do you have a pic of the swingarm right before it attaches to the Final drive....You may have gotten ahold of an Xs750/850 swingarm....It could happen and is off by that .5 inces you're talking about....chop

[Yahman]

bikerphil
The swingarm is centered in the frame with equal spacing on each side and it is set to the manuals spec. There isn't enough adjustment to move any more than an 1/8th at the most.


xschop
I noticed the right shock being off also, however the left one is square. I was wondering, if it could be the wrong swingarm.

I can give you all of the pictures you need.

[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

[IMG][/IMG]

Larry

[Yahman]

xschop

I see what you are looking for, the grease fitting is there. That would rule out an XS750/850 swingarm.

Larry

[TopCatGr58]

Hey Larry,

I hate to say/ask it, but are you the Original Owner of the bike in question?? IF not, then perhaps it's not so much the swingarm as the FRAME that may be jacked, due to an undocumented collision/spill??

You say the rear is STRAIGHT with the front, do you mean it is in perfect rolling position with the front vs. being slanted....ie.

..|

.|

vs |
..../....??

A trick I learned decades ago for evaluating whether a car's rear wheels are tracking properly with the front is to drive it over a dirt road with small amount of soft sand on the surface...could also spray sand on concrete, and the drive the vehicle in straight line over it and look at the tracks left behind, and you can see whether the wheels/tires are tracking the same line!?

Good Luck!
T.C.

[snowdog51]

top cat

i have been a mech all my life thats the coolest smartest most idea i ever heard

when i put ss lines on the front i did two lines from the mc . the mc made a nite day
improvement the ss lines 25%
as ever bill

[xschop]

enigma

I was going to add that some moron might have installed an xs750/850 axle/spacers which could be the problem. Also look at the right side swingarm to inner frame and see how much space is there between the two....It does look like an xs/xj swingarm....Also I personally don't know the info, but if the swirly wheel was from a Seca or other smaller bore Yamaha then the wheel/drive coupler could be diffrerent...This problem you have here is the strangest thing I have ever seen on these bikes, well mechanical wise....chop

[Yahman]

T.C.
I purchased the bike a couple of years ago (I have a weakness for big projects. ) and I knew it needed a lot of work. No idea what its history is. I think the problem is in the frame. I am thinking that the seat rails that extend back to the fender are tweaked a couple of degrees to the right (hard to see by eye). I was trying to avoid a lot of tedious measurements but I guess it has to be done.

The trick you mentioned was taught to me a long time ago by one of my instructors, that taught me how to align cars in college. We did it old school back then, no computers or fancy stuff. Made my living doing alignments for several years, used a computer alignment machine for that though. I still align my cars the old way. What can I say, I'm thrifty! The transmission is out of it at the moment, so it's a bit difficult to do this type of test right now.

I guess I will measure this thing "8 ways from Sunday" just to put my mind to rest on this. I think I have it figured out; this will be to confirm it. I will let everyone know what I find out, hopefully later today.

Thanks,
Larry

[Yahman]

After an exhaustive round of measuring this thing bottom to top, front to rear, this is what I have found. Everything is straight, square and is inline except for the seat rails. It starts at the last cross brace where the shocks mount. I wasn't able to see it with my eye because it's only 1 to 1.5 degrees off. That however amounts to the rear fender being .5 inches off to the right. I am still going to do the dirt road test when I get it back on the road; just to be sure it tracks right.

Larry