Bobber Rebuild: Panhead Primary Drive

Kevin is ready to install the Panhead primary drive on his custom Bobber Chopper. This is a custom application. A stock chain drive primary will not be used. Inner and outer primary covers have been discarded and the primary chain oiler is turned off at the oil pump.This assembly will be set up with a belt drive assembly.

Kevin assembles the newer, diaphragm style, clutch assembly. He drops the clutch hub into the basket. The assembly uses a maintenance free, sealed bearing. The components are held together with a retaining plate and corresponding hardware. Kevin uses a spot of Loctite on the securing hardware. The new front pulley fits over the splined crankshaft. The assembly only consists of a pulley that is locked on with a large nut. There is no compensator assembly. The clutch assembly is installed over the transmission mainshaft. This shaft is tapered with a locating key way. The clutch hub nut is left hand thread. Loctite should be used on these two important Panhead primary drive securing nuts.

Kevin installs the clutch plates. He starts with a steel plate and proceeds by staggering fiber and steel plates. The pressure plate is installed last. The plate is secured with shoulder bolts and springs. Kevin slides the new Panhead primary belt into position. He starts off with the belt very loose. The transmission is still loose on its mounting plate. Prior to setting up and adjusting the Panhead primary drive belt, Kevin removes the ratchet assembly top from the transmission top cover and installs his jockey shift assembly.

Now, he can turn the transmission adjuster bolt until correct Panhead primary belt tension is achieved.
The transmission mounting hardware can now be final tightened. After tightening the transmission, Kevin re-checks belt tension.

Kevin sets clutch adjustment at the clutch pack and moves on to the secondary drive. Kevin installs the secondary drive chain and master link. Once chain tension and tracking is set, the rear brake drum and rear axle are tightened.

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