Polish Makes Perfect

The Painstaking Process of Polishing A Motor

Our motor arrived at Precision V-Twin for disassembly down to every last nut and bolt.

First the cylinder heads were carefully removed followed by the cylinders.

With the top end in pieces, enough emphasis cannot be placed on properly bag- ging and tagging all the parts. A few extra minutes and plenty of marked zip-lock bags, versus a coffee can and a good memory will save hours on reassembly.

Before any polishing could begin, all the open surfaces were masked off to avoid debris entering the motor.

In order to polish all the tiny spaces and in between the cylinder fins, custom bits were handmade. A variable speed air grinder was necessary to avoid costly mistakes.

A flat piece of sand paper was folded into a square and a hole was punched in the center to form the bit.

Bits ranged in grits from 120, 220, 400, and 600 and lasted between one and five minutes before needing replacement. More than 800 bits were used in the polishing process.

This is where a steady hand and a large amount of patience comes into play. Any slight slip of the hand in any direction can have disastrous consequences costing hundreds of dollars in replacement parts or repairs.

Here is a shot after a rough sanding using the 120. The process needed to be repeated with increasingly finer grits. It’s a messy and slow process that requires a great amount of attention to detail.

For the cases and larger pieces of the motor, a polish- ing wheel was used. Polishing is without a doubt a dirty job with little-to-no shortcuts.

Once the motor was polished, great care had to be taken to clean all the debris and polishing compound out of the motor. The devil is in the details and required a flashlight and a cotton swab.

After a quick mock-up, the motor was back off to Precision V-Twin for reassembly.

Would you want to get open-heart surgery on an operating table that was messy and covered in blood? Your motor should be no different and a clean working area separates the good motor builders from the bad ones.

Like a giant shiny puzzle, Precision V-Twin had its work cut out to reassemble the motor to proper running condition.

Every part of the motor had to be carefully reassembled from the crank on up.

After the cases came together, it started to look more like a motor and less like a pile of parts.

Clean hands made for a clean motor as the cylinders were slipped over the pistons.

Tightened up and ready to rock, the motor looked like a shiny jewel and ready to be reinstalled in our project bike.

If shiny things make you smile, you can purchase or chrome plate almost any part of a motorcycle. There are plenty of bolt-on accessories available and for those that want to do a little more work, a trip down to your local chrome shop can have endless amounts of opportunities for parts dipped in the shiny stuff. But there’s a good reason why you don’t see many polished motors out on the road. It’s an extremely slow and precision process. Each fin of the cylinder must be painstakingly hit with different grades of sand paper to achieve the mirror-like finish. The total time to polish a motor is in excess of 40 hours and consumes approximately 800 custom-made sanding wheels. The final result is stunning and definitely sets the motor apart at shows or on the road. but the fun doesn’t stop there, as periodic maintenance is necessary to keep that original shiny luster. There are a few tricks and tips to help the process so expect to see a future tech piece on keeping a polished motor looking new.

To tackle the job of polishing the motor, we enlisted True Finish chrome located in the heart of chrome plating: Orange County, California. True Finish can plate anything from motorcycle parts to glass bottles in different finishes such as chrome, nickel, black chrome, pewter, copper, gold, brass, and more. For the motor work, we enlisted the help of Precision V-twin out of Phoenix. Will White and Adam Smith have a combined 23 years experience as Harley mechanics and know their way around a V-twin better than most. Aside from engine builds, they specialize in full bike builds, including paint. They were our first choice for making sure this puzzle didn’t loose any of its pieces.


True Finish chrome

(714) 705-6978

Precision V-Twin

(602) 569-1118

Torch Industries

(623) 842-2277