Diesel Land Speed Racer Mk2 - Part 8 - Machining the Transmission Mounting Plate

The transmission mounting plate is one of the most important pieces of the entire motorcycle, and took 3 weeks of planning to properly fabricate. I do not have access to CNC machinery or a large mill at the moment, so it was necessary to manually carve the plate using a band saw, a drill press, assorted hand files, and a block sander.

The plate must perform several functions. Most importantly, it serves as the mounting surface for one of the countershaft bearings. For the CVT transmission to work correctly, the center-to-center distance of the two shafts must be set to a precise dimension (in this case 9-3/4 inches). Therefore, the placement of the bearing block on the plate, as well as the plate's mounting location on the engine block, is crucial.

Additionally, the plate acts as a major structural component. On one end, it is tightly bolted to the engine block. On the other, it is fastened to a large threaded rod that is mounted in the central frame casting. This is extremely important,  because it allows the force from the engine to be transferred through the heavy aluminum plate, rather than through the frame tubes. It also improves the rigidity of the whole chassis.

Step 1 - Layout the overall dimensions on the material.

My "Manual CNC Machine"

Step 2 - Begin carving outer shape, and drill layout holes. Use 1 inch holes for the shafts so that the plate will accurately locate on the crankshaft

Step 3 - Locate the plate on the crankshaft, and determine the position of the hole for the large threaded rod.

Step 4 - Drill hole for threaded rod, and finish carving the rough shape.

Step 5 - Prepare threaded transfer punch.

Step 6 - Install the threaded transfer punch in each engine-block bolt hole to be used, and hit plate with a hammer to punch the locations for the bolt holes to the plate.

Step 7 - Mark out the locations of the mounting holes

Step 8 - Drill and test-fit the mounting holes.

Step 9 - Enlarge the shaft holes once the layout process is complete.

Final installation :-D