Colin

Colin,

I'm assuming that you are familiar with the general proceedures for taking apart/assembling the fork and steering stem assembly. After disassembling the steering head assembly, the lower bearing will usually need to be pressed off the steering stem with a shop press. This often requires a special plate (all machine shops have these) that grips the lower part of the bearing so the stem can be pressed through. The new bearing can be installed by chilling the stem in the freezer, warming the new bearing (boiling water works, with the bearing in a sealed plastic bag) and using a little anti-seize on the stem area where the bearing goes. It will usually just drop on or a length of thick (schedule 40) PVC tubing with the end cut square can be used to seat it. Be sure to inspect the o-rings that seal the bearings and replace them if necessary. Pack the new bearings throughly and just not just the outside of the rollers. A popsicle stick will work well to push the grease into the bearing from the edges while slowly turning it. I keep a bunch of popsicle sticks handy as they are useful for mixing epoxy, wrapped with sandpaper will get in tight spots to sand small parts and pack bearings without fear of scratching, etc. I like to use a mixture of 70% waterproof grease and 30% anti-seize compound, the same mixture I use on my suspension bearings and bushings. I like to use anti-seize on all fasteners that I don't use Locktite on, especially those of dissimiliar metals, which will normally form a type of corrosion.

This is a good time to clean the inside clamping areas on the tripleclamps to reduce fork flex. When spinning on the top preload nut for the stem assembly (the one under the top tripleclamp), just make it finger tight. When you install and tighten the top nut (the one with the setscrew) it will tighten the bearing assembly a little more. You may need to adjust the nut under the top tripleclamp a little to get the right preload. When fully tightened, the forks should swing easily and smoothly from side-to-side and the bearings should have no slack in them whatsoever. This is checked by grabbing the lower fork sliders and pulling them forward and backward, looking for and listening for, looseness in the stem bearings. Be sure to carefully inspect the handlebar clamps for any cracks caused by overtorqueing or uneven tightening.

A couple times a year, take off the top tripleclamp, loosen the preload nut to the top of the threads and spread some grease on the bearings after inspecting the o-rings. This way the bearings should probably last the life of your bike as they will have fresh grease and adjusted preload.
Let me know if you run into any problems.

Jon