The chain adjustment distance is always larger on the left. It was 0.050 inches larger in 2017 and 0.021 inches larger in 2018. It is different every time the bike is put together. The attached is made from the setup in Reply 3467 when the axle and swingarm spindle are parallel. The adjustment distance is 0.030 larger on the left. What this means is in both 2017 and 2018 the wheels were in alignment but not the sprockets. The sprockets need to be in line to get the most efficiency from the drive train.
The problem is the alignment of the upper frame, engine, swingarm and axle when everything is bolted together. This is the method I am working on. First, loosen all bolts holding the outriggers to the frame and swingarm spindle. Second, loosen the swingarm spindle and all engine mount bolts. Third, loosen all bolts holding the upper to lower frame.
Now, the rear axle is adjusted to the 0.030 inch offset as shown on the attached and the axle bolt is tightened. The chassis is jacked around until the wheels are plumb and in alignment. Then all bolts are tightened. The goal is to have everything in alignment when the job is done. The details of how to do this are being figured out.
Folks tell me that the alignment issues I am dealing with are common to many modern bikes. The multi piece frames like on the Triumph are more suited to robotic and semi-robotic assembly. It takes lots of manual labor to install the heavy modern engines in full cradle frames. Those old one piece style frames did not have this issue.