The 28 TPI bottom fork nut retains the lower fork bush and shuttle valve in the 1968-1973 shuttle valve forks. Note: the early production 1968 Triumph 650 models between VIN numbers DU66246 and DU68363 were fitted with fork stanchions with 26 TPI CEI threads and use the 97-2224 bottom fork nut.
The lower fork nut is precision manufactured in the US to original factory specifications under strict quality control. This fork nut is machined with 28 TPI UNF threads, suitable for fitment to the 1968-1973 models using the shuttle valve forks.
The special round nut has four notches cut into the flange which necessitates the use of a special spanner to tighten it into the bottom end of the fork stanchion. The nut not only retains the lower bush but has a large internal opening which allows the dampening shuttle valve to move in and out of the nut. The shuttle valve is captured with a circlip fitted outside of the lower fork nut.
The nut is threaded into the fork stanchion using a special spanner, Triumph part number 60-0527. Consult the factory workshop manual for complete fork assembly instructions.
Note: If you are unsure whether your fork tubes are 28TPI (to fit these nuts) or the earlier 26TPI type, see recommended links for our thread pitch gauges, a must for every British bike shop & enthusiast!