Poor handling may be caused by improper tire pressures, a damaged frame or swinging arm, worn shocks or front forks, weak fork springs, a bent or broken steering stem, misaligned wheels, loose or missing spokes, worn tires, bent handlebar, worn wheel bearing, or dragging brakes.
Poor handling is also caused by the steering head being adjusted too tight or too loose, or by the races and balls being excessively worn. Also, if the frame has been recently repainted, overspray on the bearing races will prevent the bearings from seating correctly and making accurate adjustment impossible.
Worn or frozen swing arm bearings will also cause handling problems. They can be checked by removing the wheel and shocks, and then moving the arm right and left by hand. If the free play is greater than 1mm (0.04 in.) replace the bearings.
NOTE: A worn or loose swing arm pivot will usually be felt through a tendency for the motorcycle to weave from side to side. A high-rate wobble indicates front end trouble.
In addition to the checks mentioned, make certain the tires are mounted correctly and that the heads are seated evenly on the rims. Tires have alignment indicator ribs around the bead and an incorrectly seated bead will be visually apparent. If this condition exists, deflate the tire and reseat the bead before inflating it.
The increasingly common practice of cutting rain grooves into road surfaces has added a totally new handling problem for most motorcycles, no matter how well tuned the suspension. It is most easily solved by using tires that do not have a center groove, If the motorcycle tends to snake, as though the swing arm pivot were loose or worn, the problem usually lies with the rear tire. If the steering is imprecise and mushy, the front tire is as fault. If all other handling factors are correct, a change of tread pattern will almost always correct the situation.