Fitted torsion bar today. This is the second one I have had to deal with. I have the standard tool to tension up the bar and pull the figure of eight into its correct position to gently tap the metal torsion bar link pin into position. I met with two problems that may be of interest. The first was that the lever arm would not sit flush against the large washer when pushed onto the rod splines in fact even without the rod it would not fit in the frame enough to allow the figure of eight link to drop between the engine lugs. I think that the very large brass bush in which the lever arm revolves may not have been sitting as deep as it could into the frame but it refused to go further in when a socket and hammer were applied. The lever arm has a curved profile where the horizontal tube meets the vertical area. The solution was to use the Dremel with a fine file to make the tube joint more of a right angle. This did the trick.
The second problem occurred on me last build. This was a failure of the special tool to pull the figure of eight arm fully into position. There was a 1/32 inch shortfall. I've the tool did not pull the link far enough. The problem turned out to be the fitting of a new rebound buffer at the rear of the engine. This was preventing the engine lugs from assuming a more favourable position. The scooter had no rear or front wheel and was on its stand and the rear frame on a buffet. Levering the rear wheel downwards was therefore not an option. The scooter was on a workbench. The solution was to wrap a tow rope over the back of the engine and under the bench. Tie the two ends together leaving two or three inches of slack, slip a crowbar through the rope and turn the rope until the engine is pulled down and the rear buffer compressed. The tool then did its job. It may seem primitively but it works.