TPS is the Throttle Position Sensor. It's a variable resistor fitted to the side of the carbouretter which tells the ignition unit how far open the throttle is, so that it can alter the ignition timing to suit.
_________________
MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball