Rear wheel alignment mystery...

cknight · Post by **cknight** » Fri Jul 17, 2015 11:01 am

Just sent you a PM. Chase

R100 · Post by **R100** » Fri Jul 17, 2015 12:55 pm

cknight wrote:Just sent you a PM. Chase

Still have not received your PM.

cknight · Post by **cknight** » Sat Jul 18, 2015 11:43 am

Appears that none of my replies made it out yesterday. Both of the swingarms are spoken for. One is to replace a unit that is twisted about 8mm. Yes, I'll probably try to straighten it after removal. Did you try G's plumb bob check? If I have some time this weekend, I'll try to come up with some other measurement checks. The back half of the frame being bent is not impossible, but that would likely put the rear fender out if line also. Your chain bending toward the right still seems to be a clue that it's the swingarm. Perhaps try to install the swingarm upside-down, slide the wheel assembly in, and see how that looks? Regards, Chase

R100 · Post by **R100** » Sat Jul 18, 2015 12:48 pm

cknight wrote:Appears that none of my replies made it out yesterday. Both of the swingarms are spoken for. One is to replace a unit that is twisted about 8mm. Yes, I'll probably try to straighten it after removal. Did you try G's plumb bob check? If I have some time this weekend, I'll try to come up with some other measurement checks. The back half of the frame being bent is not impossible, but that would likely put the rear fender out if line also. Your chain bending toward the right still seems to be a clue that it's the swingarm. Perhaps try to install the swingarm upside-down, slide the wheel assembly in, and see how that looks? Regards, Chase

I haven't posted anything more as I really don't have any definitive conclusions yet, just ideas that need checking out.

R100 · Post by **R100** » Sat Jul 18, 2015 6:40 pm

cknight wrote:I just checked two later type spare CB77 swingarms for trueness. Both have the same measurements from the outside of the front pivot bushings to the outside of the plates that hold the rear axle. The plates are right at 1.8mm inboard. The spacer dimensions you have are correct. There should be no offset from the center of the rim to the center of the hub. It would appear that your swingarm may be bent to the right. G's plumb bob is also an excellent check. Regards, Chase

Just double checking.
Were your measurements (1.8mm) done with bushings in the swingarm?
I am going to try to true up mine.

cknight · Post by **cknight** » Sat Jul 18, 2015 8:21 pm

I mis-typed earlier, the 1.8mm was without the bushings. Did the "way off" plumb bob episode show a right offset? Chase

rrietman · Post by **rrietman** » Sat Jul 18, 2015 8:45 pm

the most common bent swingarm is a result of a hard lateral hit to the rear wheel. It displaces the swingarm one way or the other, but, because of the structures involved, can leave it parallel with the centerline of the bike. I have seen this a few times on old Honda's. Of course you would want to fix it, but if the chain tracks OK, I wonder if it really affects the ridability at all? I have a CL72 right now with this happening and it rides just fine, just looks a little odd from the rear.
Randy