I'm in the process of restoring a basket case Lightning which is supposed to be 1969. However, the frame is '67, motor is '65, and front end is either '69 or '70. Assembling the forks to the frame, I found that there was no way to install the front wheel without compressing one of the forks slightly - - one appeared to be about 1/8" longer that the other. Upon dis-assembly, I found that the machining of the bottom of the fork tubes to be grossly different. (note:there is a posting on the Triumph Forum under (Front wheel - Fork alignment issue) which shows the same problem.)
The difference is about 1/8" of an inch. Also, the axle slot was out of square with the tube by about 1/4" in 10".
Was BSA really this bad at quality control? Or is one of these from a different model? I searched thru about 50 sets of used BSA fork tubes at British Cycle Supply, and actually found one exactly like the longer one shown here, including the dimple next to the axle slot, but I couldn't find the mate to it. I picked up a good useable one (on the left) but of course it would have to be powder coated. So I decided to machine them. First I squared up the slot on the shorter one, then I milled about an 1/8" off the longer one and deepened the slot.
the last photo shows the end result.
I will have to get another end cap powder coated, but that can be add at any time.
Can anybody shed light on the small dimples shown on both the fork leg and the cap? Are Triumph, '69 and '70, the same?