Slippery Turcite Fork bushings and damping upgrades

For your forks to ride smoothly with out bottoming or topping out you must install the slippery JS Turcite bushings along with the aluminum sleeves. Turcite is the best material available for fork bushings and will easily outlast Teflon. For the aluminum sleeves, plug the 1/8” diameter oil escape hole in the bottom of the fork tube (just above the lower bushing) or you will not get the necessary oil cushion to prevent “top out”. Thread the 1/8” hole with a 6-32 tap and use the provided set screws (coat the threads with red loctite to keep them in place). Make sure the set screws are not proud of the surface or installed too deeply.  For details on the aluminum sleeves (see damping sleeves).

fork spacer

 

REBOUND DAMPING:

Replace your worn aluminum damper caps with tight fitting JSM caps with a brass inner surface for longer life and improved reliability.  The damper rod shaft should measure .375″. 

COMPRESSION DAMPING:

If you have damping tubes with holes below the conical section then you need to cover those holes with JS alum sleeves to achieve a hydraulic bump stop and avoid bottoming “clunk”. Then drill only one hole in the middle of the conical section as in the photo below. The value in compression damping is reducing front brake dive and bottoming in racing – but you will feel more bumps when cruising. A single 1/16″ hole per tube in the conical section will give you noticeable compression damping (smaller than 1/16″ will cause unwanted cavitation). I recommend a single 1/8″ hole per conical section which gives minimal high speed compression damping and is good for the street. A 3/32″ hole is a compromise but you will feel more bumps. Larger than 1/8″ will give the smoothest ride but no compression damping. If you already have 1/4″ holes in the conical section then (or just above the conical section) you won’t have compression damping and that is fine. Generally speaking you do not need compression damping on the street because too much compression damping will give a harsh ride (the stock setup has no compression damping).

damp tubes

Place the Oring on the bottom of the damper tube. You must have the aluminum washer installed in the bottom of the slider to avoid crushing the Oring.

To prevent leaks at the drains, install the small Oring on the drain screw with the small aluminum ring.

Start with 5 oz of 15 weight fork oil in each leg.  Adjust damping by changing to 10 or 20 weight.  Do not use “leak proof” seals which have too much sticktion. Now you’ve got oil tight, modernized, stickion free forks with excellent damping.