Re: 75 Yamaha oil injector info needed
The pump is usually under a small cover on the right front of the engine. The tank is under the seat, or at least is usually filled under the seat. it is not a good idea to keep the pump hooked up if only using premix, as the pump's lube comes from the oil to be injected.
Fill the tank with a good grade of 2-stroke oil designed for motorcycles, i like Si& bel ray, but there are plenty of others. i like the bel-Ray as it leaves little to no carbon from combustion.
Remove the cover on the engine that covers the pump. There is a small phillips screw roughly at the top, on the side outermost towards the viewer. It usually has a small red fiber washer as a gasket. Take out this screw. Eventually, the oil will start to flow out of this hole. You may have to put a small amount of gas in the oil tank to loosen up the varnish enough for the oil to flow. At this point, you will notice a pulley like affair on the front of the pump. this should have a cable attached to it.When you open the throttle, it will open too. If not, do not use as is. Hold this pulley against the pump body the same direction that the cable pushes it when the throttle is opened. This will be towards the back of the bike. Front, back, right left are as viewed by sitting on the bike in a normal fashion and as viewed from normal rider's position. at the rear of the pump, there is a nylon wheel like affair that you can rotate to operate the pump; hold the pulley as stated above and rotate the wheel the direction of the arrow on it down when viewed as you normally would, or more properly, ccw when viewed from the front of the bike.This rotation while holding the pulley back will cycle the pump. If too new to have this wheel, then start the engine, the plunger portion will cycle in and out, and air will start bubbling out of the hole the screw was in. After all of the air is bled out, then you can refit the screw and fiber washer gasket. And turn off the engine if you had to start it.
Next, with the throttle at idle, check that the small pin like affair at the pulley I spoke of earlier. This pin should line up with a small mark on that pulley; if not, adjust cable until it does. (the engine is still off at this point.)
Now it is primed, bled and adjusted. Note that when the plunder cycles at its most outward point, there is about a .008-.010 inch gap between the end plate and the pulley we have been discussing. I just checked the manual, and it is supposed to be as above, with a minimum of .006 inch. This gap is achieved by shims between the washer-like end plate and the plunger shaft. Note that any oil you use must be compatible with oil injection systems. Yamalube and the BelRay I spoke of are. Some pre mix oils are not.
Now you're ready for the final check: see if it actually works. There is a small hose/pipe affair going from the pump up to the rear of the cylinder of the carb on the right side. Undo this at the engine end, start the engine, hold the pulley in as before, and see if the oil starts to ooze fromt the tube. It will come out in a series of gentle squirts in keeping with the motion of the plunger we spoke of earlier. If it is coming out, get rid of the pre mix in the gas tank, make sure the oil pump is still air free by bleeding it again, and check all of your hose connections. Fill the gas tank with fresh premium and top off the oil tank; last, the oil in the gearbox also lubes the clutch, so you need to use motorcycle oil, not car oil. get some at the shop you got the autolube oil at.
I used to work for Yamaha when that bike was new. Some competition types removed the oil pumps, but for farm or woods, or on/off road use, the pump is fine. I put over 50k miles on a CT1 175 and went through two cylinders and a crank due to endless use, but never once had a problem with the pump. Those pumps are as reliable as an anvil. If yours is dead, let me know and I'll mail you another, as I have several lying around here.
Let me know how it works out.