That's a tough one,,, on the one hand HD will finger point and after months of wrangling you may not get 100% satisfaction. On the other, to suffer the $$ loss and sell the bike hurts and it will only solve your issue, ie, it passes the buck onto someone else and given it's a real safety issue involved I don't know that I'd want that on my karma. Legally you might not be responsible, but, hey, if you sell the bike and the buyer comes off and gets seriously hurt or worse (a real possibility at that speed) phew,,, that's not a good thing nor would I want that on my conscience.
I think the first step would be to take it back (slowly!) to the dealer who fixed it and at least give them the chance to put the matter right. Getting MoCo involved as early as possible would be a good idea too. Go straight to the top though, don't bother with the chain of command; write to Willie G at R&D. You do hear about this issue a lot, so, hey, we can put a man on the moon, certainly we can fix a speed wobble. After all, if it happens to others - it's in their best interest to fix it. Get him enrolled in the matter and who knows what could happen.
Good luck