Forks

General
The Forks are an area that many have tried to improve. If the bike has been lowered (usually to suit the shorter rider), then it has frequently been suggested there is some merit in pulling the forks through the top yoke by a small amount.

Some riders recommend adding preload. With the stock springs, adding up to an extra inch of spacer (you can use std 32mm [1.25"] PVC pipe; the sort you fit under the kitchen sink) eliminates most of the travel you would get from the softer part of the spring since they are dual rate. More than 1" and you will struggle to get the fork tops back on. Many guys (especially those who are heavy or ride hard) do not like dual rates because the bike dives through the softer part of the spring upon braking before reaching the stiffer coils. If this is the issue you have the best way to deal with it is by getting stiffer springs.

If you already have stiffer single rate springs adding that much preload has zero effect. All it does is remove an inch of your suspension travel. Single rate springs compress at the same rate over their entire operating range so adding extra preload does not "stiffen them up". Remember the amount of travel you have is equal to the space between all the coils of the spring added together, once this space is compressed to zero (either via preload or a nasty bump) you're out of travel and your forks bottom. To overhaul the forks, you don't really need the 30mm fork tool needed to dismantle them. Loosen the bottom bolt first. Get a length of 1.25" dia plastic drain tube from a hardware store, cut a length to replace the spring, tighten the top plug onto it. This will hold things firmly enough to fully unscrew the bottom bolt.Same for reassembly, the plastic tube will hold sufficiently for initial tightening, the spring for final. A piece of 40mm (1.5") dia tube is good for driving the new seals home; you will need to slit the tube and then tape up to give a tight fit against the stanchion. Alternately, use the old seals to drive the new ones down with.

On Showa type forks, the main seals are common to the Kyaba type, but the dust seals are different.

Picture of a Showa Fork bushing that is worn.

A Showa Fork Bushing in new condition. Note the knurled finish to the surface.

Aftermarket Front Fork Part Numbers/Availability
These forks were installed on a 1999 Trophy and I am not sure what the other years are that have the same units. The Kayaba (KYB) forks were used for all others.

1) Race Tech part numbers for the “Showa” Guide and Slide front fork bushing are:

FMBI 43151 P - these are the inner bushings that are installed on the “fixed” chrome tube that is attached to the triple tree clamp.

FMBO 43152 P - these are the outer bushings that install into the lower black legs.

Note: The Showa “Factory” components “ may not” be procurable from Triumph directly!

2) Race Tech part numbers for the “KYB” Guide and Slide front fork bushing are:

FMBI 43201 P - these are the inner bushings that are installed on the “fixed” chrome tube that is attached to the triple tree clamp.

FMBO 43122 P - these are the outer bushings that install into the lower black legs.

3) The Emulator Gold Valves are the same for either fork manufacture.

FEVG S4301

4) The typical spring rates that have been used by most of the members on this group range from .90 kg to 1.0 kg. Below is a small list of springs offered by Race Tech for the Trophy.

FRSP S373210	36.7x34.5x315 1.0kg

FRSP S373295	36.7x34.5x315 .95kg

FRSP S373290	36.7x34.5x315 .90kg

FRSP S373285	36.7x34.5x315 .85kg

The factory recommendations for the various machines with regard to weight and volume of fork oil are different. As is the pull-through height setting of the forks in the triple-tree clamp. Fifteen weight or higher (10-20wt, 20 wt. or even 30wt.) filled to the suggested oil height level seems to be the norm for most owners. I am opting for 20wt. oil and raising the oil level an additional 5mm when I am done with this years service.

Race Tech Emulators - How they work