In last month's "Build-Off" article, I finished the rough motor case grinding with porting tools and grinders in my garage. This month's installment reveals the steps a professional has to take to really bring out the shine. Show-winning polish is not a quick job, and getting a championship polish from old, used cast-aluminum parts takes many man-hours of labor-intensive work.
I visited a local custom and repair shop, Let-It-Ride Custom Cycles in Bellflower, California, to guide me-and my chopped Sportster motor parts-through the polishing process. The crew there hooked me up with their polishers and did a great job. If your bike isn't already in pieces (like mine), they'll disassemble any part off any bike, have it polished, and reassemble it for you.
Juan got started on my motor...
Juan got started on my motor by sanding down each component with an electric drill and an aluminum shaft with medium-grit sandpaper wrapped around the end. The shape of the sandpaper on the edge of the shaft gets into the small nooks and crannies of all kinds of parts.
A finer-grit sandpaper was...
A finer-grit sandpaper was wrapped around the same type of shaft, slowly grinding away any casting marks.
Then a custom-made, medium-grit...
Then a custom-made, medium-grit sanding disc was used to get into the larger fin area of the cylinders and heads.
After three sanding steps,...
After three sanding steps, the polishing finally began. First, a stiff-cloth polishing disc reduced the sanding marks, and the part began to take on a dull shine.
Next, a softer, slightly less...
Next, a softer, slightly less abrasive wheel and polishing compound brought the part close to finished, but getting it all the way to show-quality would require another step.
Finally, a very soft wheel...
Finally, a very soft wheel and very fine polishing compound finished off the polish job. In this case, start to finish took six long steps. A cylinder usually takes about eight hours to polish, while a head takes four to six hours to complete.
Most components need more...
Most components need more intricate sanding tools, but some parts are composed of mainly flat surfaces that can be lightly sanded using a belt sander.
Chopped Sporty case halves,...
Chopped Sporty case halves, before and after.
Westbury Hot Rods' Hollow...
Westbury Hot Rods' Hollow Point footpegs, before and after.
Sporty rocker boxes, before...
Sporty rocker boxes, before and after.
Here's a closeup of the Sporty...
Here's a closeup of the Sporty rocker covers. Note how the polishing removed the porosity around the bolt holes-they look better than new!
Sporty heads, before and ...
Sporty heads, before and after.
Westbury Hot Rods' stainless-steel...
Westbury Hot Rods' stainless-steel Hollow Point shifter/brake pegs, before and after.
Chopped Sporty cam cover,...
Chopped Sporty cam cover, before and after.
Westbury Hot Rods' Hollow...
Westbury Hot Rods' Hollow Point grips, before and after.
Here are all the components...
Here are all the components after polishing! They're hardly recognizable as the old, dirty, cast parts they started out as-a few hundred dollars can go a long way. Details, such as polishing, make the difference between a nice bike and a show winner.