1.6 gallon (6 liter). Takes 83-up screw type gas caps. Fuel tanks are half way 3/8" internal threaded and 1/4" internal threaded on the rear end; on both left & right side. Approx. dimensions: 14.7" (37cm) long x 8.66" (22cm) wide. Tunnel dimensions: front depth 8"; rear dept 1"; 50mm wide. Tunnel width 2". Depth front 8"; rear 1". Note: It is advised to pressure test; seal and test fit all tanks before tanks are painted and installed. Some tanks are painted; but this coat is applied for rust prevention during storage only. Note: Dimensions are approximate and for reference only.