I take the bike in for it's 8000km service soon (5000 mile) and when I booked I asked the dealer about this. They said they would check it out, and that it may be the bearings in the steering neck are too tight - they also said the bike is heavier on the left because of the primary. As long as it's something relatively common and will not cause adverse wear, I guess I can live with it - I'll just pack a little heavier in the right bag.

 

Do you still have factory seat. I had the same problem. switched to the sundowner seat cured the problem.

 

Nope,... no stock seat - my back and butt couldn't take it for anymore than a few hundred Km. I have a Mustang solo with a backrest now (it's great!), and to stay straight with a very light touch on the bars (or none) I need to hang half my butt off the right side.