19342STD 850 standard piston

Norton 850 Commando standard piston – The Hipolite 19342STD is a standard bore (77mm) replacement piston for the Norton Commando 850cc parallel twin engine, covering model years 1973 through 1977 — including the Mk1A, Mk2, and Mk3 850 Commando. This is a single piston; order two for a complete set.

Made by Hipolite, the trusted British piston manufacturer with decades of heritage supplying original equipment for classic British motorcycles. These pistons are machined to OEM tolerances and are the correct choice for a standard bore engine that measures within factory spec (77.00mm / 3.031″).

Fitment:
– Norton Commando 850cc (829cc) — 1973, 1974, 1975, 1976, 1977
– Mk1A, Mk2, and Mk3 850 Commando
– OEM Part Reference: 06-3838 / 19342

Specifications:
– Bore Size: Standard (77mm / 3.031″)
– Compression Ratio: 8.5:1
– Engine: Air-cooled parallel twin, 77mm x 89mm bore & stroke
– Piston rings, gudgeon pin, and circlips sold separately — see our listings for matching Hepolite ring sets

Note: Verify your cylinder bore size before ordering. If your barrels have been rebored, you will need an oversize piston (+.020, +.040, or +.060). Contact us if you need help identifying the correct size for your build.