The motorcycle 1927 AJS Big Port 500cc racer is equipped with pannier petrol tanks bolted together, and an auxiliary oil pump on the separate oil tank.
Early Big Ports motorcycle use an inverted U-shaped steel stirrup to hold down the cylinder head and barrel - there are only two nuts to loosen when removing the head. There are no cylinder barrel base nuts, it all comes free very easily. The secondary oil pump on the side of the oil tank is operated by a small foot pedal on the timing side of the machine, and is used when the bike is being run hard and need an extra shot lubrication. A standard type oil metering device is attached to the engine as well, which under normal touring use is all the oil needed. More specs and user manual of AJS Big Port 500 you can see in next overview.