April 24, 2014

Building a Harley-Davidson VL: Transmission Rebuild

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For my ’33, I decided to go with the standard 3-speed transmission.  There was also a 3-speed with reverse available that same year for sidecar use, but I think the standard 3-speed will suit my needs just fine and from talking with those that do run sidecars, the rig is light enough that you can manage it without reverse.  I started out with a ’32-’35 case, which is easily distinguished from the previous and later models by a large mounting boss located behind the main sprocket which is used for attaching the primary.  The case was in excellent condition and only needed surface cleaning to prep it for building.

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For cleaning, the transmission case was treated to a trip through the blasting cabinet before the surface was scrubbed down with a wire brush.  Then the case was thoroughly blown out with compressed air and cleaned with lacquer thinner.  All the other original parts went through this same process and some parts like the transmission lid and kicker assembly also got a coat of fresh paint.  The top transmission studs were left in place and cleaned with a wire brush on a rotary tool while the bottom studs were removed, cleaned and reinstalled with sealant.  The gear cluster had some burrs on multiple teeth, so it was spun in a lathe and the burrs knocked off with sandpaper.

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After a few hours of cleaning, assembly could finally begin.  The first task was to replace the mainshaft bearings with a set of sealed bearings available from Replicant Metals.  Installing the new bearings was definitely a two man job and required first heating the case while the bearings were cooled in snow.  This provided just enough clearance that the new bearings could be tapped into place with a wooden dowel.

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Once the bearings were in place and the case had cooled down outside, it was time to install the mainshaft, main drive gear and slider gear.  I used a new mainshaft and slider gear from Eastern Motorcycle Parts as my originals were badly worn.  The mainshaft was given a light coating of red grease before being inserted through the left side of the case.  Then the main drive gear and slider gear were installed on the mainshaft.  With the gears installed, the mainshaft was pushed all the way through the case until it extended out of the right side.

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Now it was time to install the countershaft.  Again, I decided to replace my used countershaft with a new unit from Eastern Motorcycle Parts.  Since the countershaft is fixed, the gear cluster contains two sets of bearings for it to spin on.  These bearings were replaced with new rollers and packed with fresh red grease before being fitted inside the gear cluster.  The red grease also served to hold the roller bearings in their cages as the countershaft was inserted through the gear cluster.  Special washers were installed on the left end of the gear cluster to set the end play.

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The last internal component to install was the shift fork assembly.  The shift fork rides on it’s own shaft which mounts just behind and above the mainshaft.  The fork attaches to the slider gear and it is the movement of the shift fork which changes the gears on the transmission.  Where the shift fork rides on it’s shaft, there are two indentations which line up with a spring loaded detent on the the transmission cover.  When the transmission is placed in second or third gear, the spring loaded detent locks into one of these indentations to hold the transmission in gear.

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With the internal components installed, both shafts were locked in place on the right side of the case.

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The kicker assembly came next with the first half of the assembly being installed on the end of the mainshaft.  This included a spring loaded set of gears as well as two keys to keep them from spinning on the shaft.  This too was a two man job, needing one pair of  hands to hold the gears in place against the spring while the other set installed the keys.

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The second half of the kicker assembly is housed in the kicker cover and includes the kicker arm and pedal.  This entire assembly was bolted onto the side of the transmission using NOS nuts and washers along with a new gasket.

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The transmission lid was installed in the same fashion as the kicker cover, with NOS nuts and washers and a new gasket.  The finishing touch was some new alemite grease fittings which technically were no longer needed since I upgraded to sealed bearings, but still gave the transmission the correct look.

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All that is left is to mount it into the frame and add transmission fluid.

For more in depth articles on this project, check out Riding Vintage.

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Filed under Engine & Transmission, Panhead Jim's Blog, Restoration by PanheadJim

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