I´ve had my 71 TS 250 since 1977. To check to see if the injector is working I took a manual (old fashion) hand oil pump and fill it with injector oil and then remove one of the injector lines. Star the bike and hand pump the oil into hole where the oil goes into the engine while the bike is running. I pull the injector cable to get max output of the injector pumping and you shhould see oil coming out of the oil line. Do this with both lines. I did have one that was bad years ago.