AJS & Matchless Owners Club Sample Newsletter

Disclaimer: This information is provided "as-is" and is believed to be correct. Neither the AJS & Matchless Owners Club nor the author accepts liability for errors or omissions. Sorry, this is a screwed up world we live in :(

The subject of wet sumping and methods to control it have been discussed at length for several years. A few years back, Don Madden came up with the idea of controlling oil seepage by machining the oil pump plates and installing "O" rings. This modification has been printed before in the Matchless News and received with appreciation by many people. I recently received a request from a person in Zimbabwe asking me about this modification. I spoke to Don and he sent a copy of the original article reprinted below. I would like to add that the "O" ring that Don mentions from Honda now retails for $1.75 and is not normally stocked for today’s Honda’s. It can be ordered however. An alternative supply exists with almost every NAPA auto parts store or any bearing supply house where the same size "O " ring retails for $.25 to $.30. Dave

AJS / MATCHLESS TWIN OIL PUMP MODIFICATIONS

by Don Madden

Remove oil feed pump. (The narrower one mounted toward the front of the plate) and disassemble. Pump plates may be separated by tapping the drive gear shaft on wood bench or block.

Clean and inspect for wear, scoring or damaged gears. Minor wear or scoring on inside of end plates may be corrected by lapping on a flat plate. (a piece of window glass works well for this if it is properly supported from beneath…Dave) Be sure the contact surfaces of the inner, outer and middle plates are smooth as no gaskets are used between them.

Counterbore end plates on inside per drawing. No "O" ring is needed on inner plate driven gear as the bore is covered pump-to-plate gasket. Use 9/16 counterbore with 7/16 pilot. This is a common machine shop tool and is readily available. Various sizes of pilots are available and interchange with the counterbore tools. A drill press may be used but set the vertical travel stop to prevent the tool from cutting too deep. Remove any burrs or sharp edges to prevent damage to the "O" ring.

Install 3 "O" rings per drawing. Honda P/N 91301-200-000 fits well and is readily available. They are used to seal valve guides to the head on several Honda engines including CB350F four cylinder machines.

Lubricate and reassemble the oil pump and refit to engine.

Another source of oil seepage on 1960-63 engines is the oil pressure relief valve located slightly in front of the oil pump. This is the spring loaded piston assembly which is located inside the timing side of the oil filter tunnel. When the valve is opened by excess oil pressure, it passes oil from the filter tunnel to the timing chest. Many engines will also let oil seep past when the valve is closed. To check the valve, remove the timing cover and wipe down the pumps and the end of the valve, which is the 1/8 inch button projecting from the case and retained by a snap ring and flat washer. If oil seepage is seen, it is easy to fit an "O" ring.

Remove oil filter. Cut and fit a length of wood long enough to fully depress the valve when the filter is replaced with a few turns.

With the valve now depressed, remove the snap ring and washer on the timing chest side. Slide a 1/8 inch bore "O" ring on the shaft and replace the washer and snap ring. The thickness of the "O" ring is not important but I use 1/16 inch.

Remove wood block from inside filter tunnel and replace filter and timing cover.

Don Madden