The 28 TPI bottom fork nuts retain the lower fork bushings and shuttle valves 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 set of lower fork nuts are precision manufactured in the US to original factory specifications under strict quality control. These fork nuts are machined with 28 TPI UNF threads, suitable for fitment to the 1968-1973 models using the shuttle valve forks.
The special round nuts have four notches cut into the flanges which necessitates the use of a special spanner to tighten them into the bottom end of the fork stanchions. These nuts not only retain the lower bushings, but have large internal openings which allow the dampening shuttle valves to move in and out of the nuts. The shuttle valves are captured with circlips fitted outside of the lower fork nuts.
The nuts are threaded into the fork stanchions 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!