Unlike other aluminum sleeves, these are slit so they can be pushed into place by hand and have just the right tension so they stay located where they belong and don't move. The top sleeve covers up the large oil bleed hole in the fork tube when it nears full extension, thus creating a hydraulic bump stop to eliminate the harsh metalic "clunking" sound of Norton forks. Special short 1/8" plugs (not shown) are provided for blanking off the oil escape hole at the bottom of the fork tubes just above the lower bushing in order to make this kit really work.

The bottom sleeves fit over the bottom of the damper tubes to cover the oil bleed holes below the conical section. Then a hole is drilled just above the cone to create a hydraulic bump stop to prevent metal to metal bottoming. No machining required.