| Diagram | CRANKSHAFT AND CONNECTING RODS |
| Subsystem | engine bottom |
| Listed in parts books | Not catalogued by year yet |
Piston complete 9:1 C.R. T120 & T120R
Complete 9:1 compression piston listed for the Triumph T120 and T120R.
CP206 is a complete piston listed in the catalog as a 9:1 compression ratio piston for the T120 and T120R. The CP prefix is the old Hepolite/Wellworthy style piston coding, which is how a lot of these pre-unit and unit-era pistons show up in the parts books even though the number looks nothing like a Triumph part number at first glance.
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The catalog entry ties this one specifically to the T120 and T120R, both of which fall under the 650cc unit twin family. It's listed as a complete piston, meaning it should come as the piston itself along with its pin and circlips, though our record here doesn't spell out rings or exact kit contents.
It shows up in the crankshaft and connecting rods section of the parts book, which is standard placement for a piston entry even though the part itself lives up in the barrel, not down at the crank. Compression ratio and bore work vary by engine rebuild history, so if you're matching this to a specific motor, check what's actually in there now before ordering.
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