When your running down the road can you let go of your handlebars and track straight?
Alot of people indicate they never have been able to get their BD to track straight but I have corrected this issue on both an older 03 BD Chopper LSD I had, which required some extensive work, and my newer K9 RSD. Both bikes always pulled slightly to the right. Eventually I discovered two secrets about the front end:
A) Fall out is critical
Checking Front End Fall
1) Place bike on a lift and in the air.
2) Hang a ruler from each end perpendicular to the bikes front fender at the front edge of the fender(this is just my method there are a number of different ideas out there.
3) Place a piece of tape on the tip of the front fender and locate the center of the fender.
4) Gently tap the front end to the left or right until it flops over. At the point it first starts to flop, make a mental note of the distance it traveled on the ruler.
5) Repeat this in the opposite direction. The distance between the two marks should be between 1-2 inches.
6) Tightening the bearing preload will increase the distance the font end moves before it flops and loosening the preload will reduce the distance before it falls.
7) A loose front end can result in a high speed wobble and too tight and the bike will tend to wander as it is going down the road.
8) Keep in mind, the fall away will not be centered due to the weight of the brake caliper and rotor on the left side of the front end.
B) Proper front end alighnment, if you can really call it that, is critical
Of course the two above listed items are dependent upon the mechanical being in good condition i.e. your fork oil doesn't need changing or worse to be rebuilt GasMan has an excellent post here for this
http://www.bigdogbiker.com/forums/how/2498-how-service-your-forks.html, bearings are good e.t.c.
The 2nd trick I learned from a Temecula, CA bike mechaninc. When I could not find a mechaninc who could solve my issue in San Diego I ended up there. The mechanic said all they do is loosen all the front end bolts, force the bike, via the front tire against the wall and while against the wall they tighten up the front end starting at the top and working their way down to the axle. Now I know to some this may sound unorthodox others may even say its stupid but I can only tell you that when I set my front end up in this manner the bike tracks straight. Of course the back tire needs to be in alignment as well but that is a whole different post.
The above procedure only applys to our types of bikes, as far as I know, and it does not take into account any issues you may have with all the other items i.e. transmission, motor, swingarm e.t.c. on you ride. As I mentioned earlier my 03 had major build issues that took me a week, part time, to fix. However, when I got those issues fixed and followed the above alignment procedure that bike tracked straight also.
I'm no exprert by any means and I only speak from personal experience so follow my examples at your own risk I take no responsibility.