BMW R1100/1150RTs were notorious for pulling to the right or PTTR. 1000s of customers were told, "they all do that, don't worry about it."
I cried
My first RT the '98, had PTTR very badly, so I did some reading on the internet and found that there was a 2mm shim between the final drive and the rear wheel. Once that shim was removed, PTTR went away (if you had it to begin with). I never saw a reasonable explantion anywhere and never got one at a dealership on what caused PTTR or what the purpose of the 2mm shim was. Fact is, I've now owned two RTs ('98 and '00) both had PTTR with the shim which I removed resulting 100% cure of PTTR.
All that said, moving the rear wheel on an RT 2mm to the right totally eliminated PTTR for me and 1000s of other RT owners. Is there any way the rear wheel on your Rocket can be adjusted 2mm (or 1mm or 3mm) to the left? It would stand to reason, that has a strong chance of eliminating your PTT
L.
BTW: my theory on the sole purpose of that shim is that some BMW engineer designed a consumer adjustment into bikes that may have been misaligned when assembled and the design was such that said misalignment could only occur in one direction eliminating the need for a consumer adjustment to the left.