|
To do it right with MM parts, you change the oil pump shaft and either the camshaft, or change the oil pump drive gear on the camshaft. The oil pump shaft gear ratio is different for a distribuitor than for a magneto system. It should be fairly straightforward to remove the camshaft. To remove the oil pump shaft, remove the setscrew in the front of the crankcase, near the fan bracket. It should be locked with a nut.
Then remove the oil pump assembly from the block, should have 4 nuts and 1 bolt. Some may have 5 nuts.
The oil pump gear will probably stay on the oil pump shaft. Tap the shaft upward about 1/8". then tap the shaft downward from the top. There should now be a gap at the top of the gear you can hook something over it and pull it off the shaft. There will be 2 woodruff keys in the shaft, remove these and you will be able to pull the shaft and top bushing (The part the setscrew held) out the top of the crankcase. Sometimes it takes gentle tapping with a long punch to get the shaft out, because of sludge on the shaft.
The ZA and R oil pump shafts should interchange, and if you want to, you can swap the camshafts as well. (That's what I would do. Keeps you from having to change the gears between shafts.)
The timing mark on the crankshaft gear, when you put the camshaft back, is directly opposite the #1 crankpin.
|
