Motorcycle Repair: yamaha PW80 autolube, yamaha pw80, stroke oil

Question
Hi Jack, Thank you for giving your time to this site. My son rides a Yamaha PW80. Drips of oil coming from the exhaust lead me to believe that the two stroke oil pump auto lube is incorrectly adjusted. Can you describe the correct procedure to adjust the amount of oil flow? The chassis and engine number is 4BC-035624 it is approximately a 1985 model. We live in South Africa. Many thanks in advance. Steve.

Answer
Hi Steve, and you're welcome!! Ok Steve... it is not unusual at all for a dark (black) oily substance to be coming from the exhaust. It happens at where the header attaches to the head and sometimes at the rear of the pipe as well. The Yamaha Autolube injection system is one of the most reliable of them all. Given that the engine is quite old, I first would look at a few other things to determine if the injector is over pumping the oil. First and foremost, is the engine oil-fouling the spark plug more so than normal? If yes, then check the compression first, if compression is low, the rings are prolly worn and excess oil is slipping past them and out the exhaust port. If compression is normal than you may just be suffering from carbon/tar build up in the pipe. The solution to that is to de-coke the pipe. BUT... if the spark plug isn't fouling and there is no decrease in engine performance, then I really wouldn't worry about the drops of oil. It is prolly just from over 20 years of usage and some unburnt oil has gathered in the pipe. As far as I know, there is only one way to adjust the oil pump injector, and that is on the cable that runs between the injector and the throttle cable. Usually the adjuster is where the cable meets the injector pump. Make sure the slack on that cable is the same as the slack (freeplay) at the carb and you're all set!!! Hope this helps Steve and tell your son to ride SAFE!!

Jack