A rebuild kit for the Briggs & Stratton 400 and 422 series L-head opposed twin engines of 16 to 18 HP. The kit contains two standard 87mm pistons, two ring sets with three-piece oil rings, two intake valves, two exhaust valves, the complete gasket set (head, valve cover, intake and exhaust gaskets and small O-rings) and the crankshaft seals. Connecting rods, bearings, valve springs, camshaft and lifters are not included. It fits models 400400, 400700, 401400, 401700, 402400, 402700, 404700 and 422700, with cast-iron sleeve or aluminum bores, horizontal or vertical shaft. These are flathead engines with the valves in the block beside the cylinders; if the valve covers sit on top of the cylinder heads, the engine is an OHV twin and this kit does not fit. Standard bore is 87.28 to 87.31mm (3.4365 to 3.4375 inches). Before assembly, check each bore for taper and out of round, check ring end gap and groove side clearance, lap the new valves and set the valve clearance to the service manual figure.
- PISTONS, RINGS, VALVES, GASKETS AND SEALS - Two standard 87mm pistons, two ring sets with three-piece oil rings, two intake valves, two exhaust valves, the complete gasket set and the crankshaft seals. Connecting rods and bearings are not included.
- FITS BRIGGS & STRATTON 400 AND 422 SERIES - The 16 to 18 HP L-head opposed twins, models 400400, 400700, 401400, 401700, 402400, 402700, 404700 and 422700, cast-iron sleeve and aluminum bore alike.
- L-HEAD ENGINES ONLY - These are flathead engines, with the valves in the block beside the cylinders. If the valve covers are on top of the cylinder heads, the engine is an OHV twin and this kit does not fit.
- STANDARD BORE, 87.28 TO 87.31MM - That is 3.4365 to 3.4375 inches. A bore worn past that, or one that has been bored, needs oversize pistons.
- MEASURE BEFORE IT GOES TOGETHER - Check each bore for taper and out of round, check ring end gap and groove side clearance, lap the new valves to their seats and set the valve clearance to the service manual figure.