Update. I set the bike up again with the wheel alignment jigs, and very carefully adjusted the rear wheel back to the factory setting, with the axle sliders the same length from the rear of the swingarm on left and right sides. I turned he front wheel until it was parallel with the rear wheel, and measured the offset at the front between the jig parallels. With this setup, the front wheel is 7/8" offset to the left. In this picture you can see the 1 3/4" gap on the right side of the wheel, while the left side is just touching the jig. Something is clearly not right.
View attachment 81230
I was unable to use a tram gauge to check the rear axle to swing arm pivot distance on both sides. I would have to either remove the primary case or make up some offset tooling to do so, and just didn't have the time for that today. Maybe later. I did use straight edges and a digital angle gauge to measure if the wheels were parallel in the vertical axis, and they are off by 0.9 - 1.1 degrees, so something is bent/twisted. I used a pair of bars in the rear axle and the swing arm pivot to check if they were parallel, shown below.
View attachment 81231
They measured off by 0.15 to 0.20 degrees, but my measurement accuracy is in the 0.1 degree range, so those measurements aren't too significant, except to say that the difference in the wheel angles is not from swing arm twist. The rear crossmember in the frame just above the swing arm pivot is also parallel to the rear axle and pivot, at least within my measurement accuracy, and measures 1.0 to 1.1 degrees off from perpendicular to the front tire.
It looks likely from all this that I may have something like a 1 degree or more twist in the steering head. A little simple geometry shows that a 1 degree twist at the steering head would give about 5/8" offset at the bottom of the front tire. That's close enough to my 7/8" measurements to make me suspect it as the primary problem, but I really need some more measurements to be sure. With a little more effort, I could tram the axle to swing arm pivot measurements, and check the sprocket alignment.
This is interesting preliminary stuff, but I'd like a little more accuracy and detail. In the old days, I'd just take it to the local Computrack facility, but they've been out of business for a while now. I just discovered that Race Tech, the suspension gurus here in SoCal have a similar frame checking system called MEGA M.A.X., that can check all sorts of frame dimensions with the bike still mostly assembled. They charge $250 for a complete measurement survey, a not unreasonable amount for the labor time it takes. I'll give them a call tomorrow to see if they can also straighten the frame after measuring it. Their web site only mentions measurements, so I'm not sure if they also do the repairs.
I could borrow my friend's precision adjustable frame jig, but I'd have to completely strip the chassis to use it, and I'm only willing to do that if I'm sure it's needed. I kind of suspect that I'll eventually have to do that to straighten the frame, but I'm still hoping for a miracle.
Ken
