I have a 2007  1300VS Touier . Have trouble with it riding a straight line  , Acts like it  wants to snake on the road feels  . It has all the factor parts includes the 24 " windshield very mean in the wind . do you have Ideas on this . also the factor handlebars  that there is no riser for  it .    Have put on a 15"  windshield  helps but still wants to try to drif on you  also handle bars with a 12" pull back ?  

Sounds like it could be the tires or the steering head bearings. I assume your  tire pressures are correct?