Triumph 650/750 Breather Modifications
Breather line connected to TDC hole
The location of addition of breather spigot depends the year of the unit construction 650 engine. Triumph 650s for the 1970 model year, and all years after that do not need an additional breather line. Triumph 750s also do not need and additional breather line.
1967, 1968 and 1968 unit-construction 650s can have an additional breather line connected to the timing Top Dead Centre hole at the back of the barrels. The Triumph tool part # is modified to add a spigot to connect an additional breather line. The new line should be a rubber oil line connected to the stock breather line. Do not use a clear plastic line. The breather line should then be connected to the oil tank and continue on to a Yamaha XS650 reed valve as this helps create a partial vacuum in the engine which improves engine performance. A schematic of the breathing system, is supplied with crankshaft for these years of Triumph unit construction engines.
Contact us for information on breathing improvements for 1963, 1964, 1965 and 1966 engines.