Motorcycle performance guides
Performance changes on a street bike work best when they're made in order and matched to each other. An exhaust is usually the first modification, and the V-twin exhaust systems article compares slip-ons, full systems, and the brands that fit common cruisers. Any change to how the engine breathes affects fueling, so read intake and fuel tuning before deciding whether a slip-on needs a fuel controller or a full system needs a dyno tune.
On the chassis side, setting suspension sag is the first adjustment to make. It costs nothing but a tape measure and half an hour, and every damping change after it depends on getting it right.
Guide
Intake and fuel tuning
How fuel injection and carburetors respond to a freer exhaust, the signs of running lean, and the tuning options.
Guide
Setting suspension sag
Measuring static and rider sag, adjusting preload, and telling when the spring rate is wrong for your weight.
Article ·
V-twin exhaust systems
What scavenging does for mid-range torque, slip-ons versus full systems, and how Vance & Hines, Cobra, and Drag Specialties fit V-twin cruisers.