whats the best way of checking it.

 

the marks on the rear swing arm

 

Acually those can be a little off.The hash marks on the arm are spaced out almost 4 millimeters. That can be hard to make an acurrate adjustment with the eye. The best way to make sure the wheel is on straight and not cocked, measure from the back adjustment blocks to the end of the swingarm with a 6 inch ruler (precision ruler) you can get this at a home depo or sears for under $5. That way you can be sure that the measurment will be the same on both sides. I use the millimeter side of the ruler and you will be surprised on how far off some peoples wheel is out of line. Even though it LOOKS even it can be off some 3 millimeters by using the marks on the swingarm.

 

I don't use the hash marks on the adjustment blocks. I do this instead......

http://www.motorcycle.com/mo/mcnuts/chassis.html