1928 AJS Installation Instruction Manual

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Oil delivered at “6″ goes to the big end, while that delivered at “5″ goes up to the cam box. The bottom end of the plunger also has a slot, which registers alternately with inlet ” 7 ” and outlet ” 8,” and is responsible for returning the oil from the sump to the tank. It is of greater capacity than the supply pump. To dismantle the pump, proceed as follows :— 1. Remove all pipes from the pump. 2. Remove pump from engine. 3. Remove the two nuts “A” and the pin” 3 ” from the pump. 4. Gently push the plunger out of the pump body in the direction of the arrow “C” on the drawing. To re-assemble, the reverse sequence of these operations is, of course, followed. Should it be required to remove the worm ” 2,” the brass bush ” D ” which screws into the body with a R.H. thread, must be removed first. It is of the utmost importance that the nut “A” always makes an air-tight joint with the body ; and should there be no oil returning to the tank at any time, check this joint immediately. Occasionally go over all the oil pipe unions and nuts to see that everything is tight. Should one of the unions come loose, especially on the inlet side of the pump, of course, the whole system of lubrication fails. As will be seen from the illustration, the oil pump itself is very simple. There are only two moving parts, and it is most unlikely that anything in this pump will get out of order. Should the oil not be circulating and running back to the tank, be quite sure that there is plenty of oil in the tank and that the filters are clean, before dismantling the pump. Should it be necessary to take the oil pump from the engine, make certain that the short piece of square tube which drives the pump spindle from the engine is replaced. The pump delivers oil to the big end via holes drilled down the driving side of the crank­ case, then through holes in the main shaft, up web of flywheel, and through the crank pin into the big end. Oil is also taken to the cam box. A portion of the cam box projects inside the chaincase—the end of this projection is open ; the oil from the cam box falls on to the vertical chain—from there it falls through holes in the crankcase into the sump, and is returned to the oil tank. The piston and little end of connecting rod are lubricated in the ordinary way by splash from the big end, but we have found it necessary for continued high speeds on track or in road race, above (say) 60 m.p.h. average, to take an extra supply of oil direct to the cylinder walls