Triumph 750 Complete Low-Compression Piston Set w/Rings Genuine Hepolite 1979-83 PN# TBS-20432

The Hepolite story begins in 1907, when Hepworth and Grandage was formed. Today, genuine Hepolite pistons are designed for specific applications and are available in oversizes to .060″. This complete piston set includes piston rings, gudgeon pins, and circlips. Suitable for fitment to the 1979-1983 Triumph 750 twin-cylinder models originally fitted with 7.9:1 compression ratio 76mm pistons.

These pistons (71-7085) are the 76mm 7.4:1 compression ratio lower-domed crown type and are suitable replacements for the 7.9:1 ratio Triumph 750cc TR7V, T140D, and T140E models from 1979-1983. Can be fitted to the earlier 750 twins when a lower compression ratio is desired. Not compatible with the early 724cc models prior to engine numbers T140V XH 22019 and TR7V AH 24040. Cast from low expansion silicon alloy, these pistons offer excellent thermal properties and long service life when paired with premium Hepolite piston rings. Sourced in the UK.

The pistons must be fit to the cylinder barrels when over boring. The machinist measures the pistons and performs the cylinder boring and finish honing to a specified clearance. The piston rings are checked and adjusted for the proper end gaps prior to fitment to the pistons. It is advisable to replace all of the top end gaskets, push rod seals and sealing washers when pistons and piston rings are renewed.

Failure to achieve proper fitment of the pistons and piston rings can result in a noisy engine, with high oil consumption. Following the proper installation procedures, as outlined in the factory workshop manual is recommended when fitting new pistons and rings. This job requires specialized tools and skills and may be best left to a professional mechanic to carry out the task.