Tutorial: How to replace a Harley-Davidson starter motor step by step

In this practical article, we will perform a step-by-step process to replace the starter motor on a Harley-Davidson motorcycle.
Although it may seem like a complex operation, especially since it involves opening the primary transmission crankcase, we'll see that it can be performed with "normal" hand tools and only requires following the workshop manual for the model in question and a little patience.

Choosing a good candidate
When we have definitively confirmed that the machine's starter motor has reached the end of its useful life and we decide to replace it, we can either use the original spare part, or for practically the same price, slightly upgrade this component.
If, for example, our model has the typical original 1.2 kW engine, we can turn to aftermarket manufacturers and find a 1.4 kW replacement, with more power and ease of starting for a similar financial outlay.

It's important to know that if we use a more powerful starter motor, it's not always necessary to install a larger-capacity battery, but it is essential that the battery is in good condition and that the battery cables are also checked.

Preparing the operation
One of the keys to success in any repair is having all the tools and spare parts necessary to complete the job before starting , so we must first read and understand the procedure in the workshop manual and then verify that we have all the necessary gaskets, oils and tools to avoid surprises.

Gaining Access
We've chosen a Twin-Cam Softail model as an example because it's one of the most complex to build, requiring the removal of the oil tank. For other models, removing the exhaust is all it takes to access the engine.
Safety always comes first, so we'll start by disconnecting the battery terminals to avoid problems. In this model, we'll also remove the battery from the motorcycle, as it's located inside the oil tank.

Before removing the oil tank, we will empty it by removing the drain screw and then separate the trims from the sleeves by pulling them apart.

Next, we will disconnect the oil lines by gently pressing on the retaining clips and gently pulling them outwards (it is important to mark or remember where each connection is located to reassemble them correctly).

We continue by removing the protective plastic from behind the fender and loosening the two screws holding the oil tank in place at the back.

Now we just need to release the front support and we can remove the tank.

Working in primary school
We continue the process by draining the primary transmission sump by removing the screw from under the clutch cover.
We will loosen the screws on the primary cover and remove it, exposing the starter pinion.

This pinion is attached to the starter motor by a small, long screw locked by a tab that we bend to unscrew it.
Once we have the pinion loose

We can now disconnect the cable coming from the battery,

loosen the 2 screws holding the starter motor itself at the back and remove it.

Before mounting the new engine in its location, we will clean the entire contact area with the rear of the primary crankcase of rust, as this is essential for its proper functioning because this connection acts as the electrical ground for the starter motor.

Assembly and testing
We will assemble the unit in the reverse order of removal, paying attention to the tightening torque and remembering to top up the appropriate oils.
After checking that there are no leaks and everything is in place, all that's left to do is press the start button and enjoy the "magic" of electricity.

Frank Burguera

#harleymechanics