|THE EIGHT BASIC FORK TIPS
1) Check upper stem bearing fit on stem; if it can be wiggled
at all it's loose and will affect the handling drastically.
Loctite will do in a pinch to tighten it up if you're fast at
adjusting bearings. Stock stems are tubing whanged into shape,
meaning they're soft and thin. Far better is new thick-walled
well-fitted precision made stem. Replace bearings if needed.
2) Remove springs, wheel and fender, drain your fork oil and
flush and try the fore-aft play of each slider on tube at several
positions. If they have as much as 1/40" or .6 mm movement at
axle end the bushings or sliders are worn and need renewing.
3) Make sure seals and dust boots aren't dragging; you can take
seal garter springs out and run w/o dust boots if indicated.
3a) Better damping valve response by shimming the parts will
usually improve fork action. Use CPSO fork fluid, which has
polymer- and metallic-based antifriction additives and really
4) Remove tubes, hone fork clamp eyes with a bra ke hone just
enough to get paint and mung out, clean eyes, pinch slots and
tubes thoroughly with carbie spray, air dry or wipe with dead
clean paper towel, and re-install w/o touching mating areas. Trash
the pinch slot stop washers if you have them, use torque wrench on
the clamps and don't go over the values given.
5) Check rim play to see if your wheel bearings are properly
fresh and tight. Ideally you set up wheel bearings by measuring
lateral play of axle, torqued, then change exactly that amount by
precision shimming outer race or trimming spacer.
6) Check balance w/ tire off first as this is sign of
out-of-round wheel; if this shows up check rim with dial indicator
and true it as needed. Tighter spokes won't loosen up when bedding
in but tension doesn't improve wheel stiffness and too tight means
more broken spokes.
7) Make sure SH bearings are not overtight; I'll repeat: set
proper preload on first inner nut and then on outer nut, then BACK
OFF the inner to lock it. If you do the opposite you've put
extreme preload on bearings because of slop in the threads. This
way it's consistently set and easily adjusted tighter or
8) Paint doesn't withstand pressure well and always causes
creep in joints, so clean it off at points where axles clamp into
fork and swingarm or mating surfaces of any other bolted joint.
Careful assembly of fork is a vital point and you must leave
springs out til last so you can continually try the travel as you
build, correcting anything like fender mounts that pull.
8a) Fork alignment is checked easily and accurately by sighting
between tubes at illuminated background and moving head til the
tubes overlap. If not parallel there will be point of light
between them that moves up and down. If parallel, the light will
wink out at once over the entire visible length.
8b) Two words ... fork brace.
Hoyt McKagen, November 29, 2000.