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Oil pump mods

The pump itself can be taken care of, too.
Arthur has done 3 things:
1- drill the main pumpshaft to make it lighter
2- machine the sprocket to make it lighter
3- have 2 o-ring chambers machined to replace the original gasket.

Item 1 isnt doing much but the weight shedding in considerable.

Item 2 is fun, as the gear itself is 15mm thick. Arthur has machined this to 8mm, just like in his racer. After all the track kms at full throttle it showed no sign of wear at all. These, and the other gears, will survive the engine many times over!

Item 3  is done to eliminate the gasket which sometimes damages when removing it from the cases. Sometimes they stick so well to the pump housing it can’t be removed without breaking the gasket somewhere.
To tackle that problem, Arthur had 2 chambers made to fit o-rings, just like on the modern Ducati bikes. The suction has 12.7 x 2.62 and discharge 9.2 x 2.62mm o-rings. The chambers are diameters 18mm and 15mm respectively, and the depths 2.2mm.

Note: the pump housings are cast, and when examined carefully you will find casting ridges in the holes for the suction/discharge. Remove these before the vibrations and flowing oil do!


oil pump mainshaft drilled out for weight saving.
oil pump gear wheel thinned for weight shedding, front side.
oil pump gear wheel thinned for weight shedding, back side.
oil pump gear wheel total thickness 8mm.
oil pump with o-ring chambers, hollow main shaft and lightened sprocket.

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