Installing 103ci Stage Kit 1 - 103 Cubic Inches Of Harley

A feed line sends the hot oil to the cooling chambers, and a return line sends the cooled oil back to the motor via the adapter assembly. The cooling system features an internal thermostat, which opens at approximately 185 degrees. The cooling unit mounts between the lower framerails in front of the voltage regulator.

With the bottom end pretty much together, Danny was ready to bolt it back into the frame.

After applying some thread locker to the mounting bolts, the motor and trans were joined together once again. The oil lines were then connected and secured with new hose clamps.

To dress things up a little, we added this chrome oil-hose cover, followed by...

...a chrome oil-filler spout cover.

The spout cover has a hole at the top to install an oil vent line, so we also added this chrome oil-vent line. To properly install the vent line, Danny slid the motor side of the line in first, which allowed enough room to slide the other side of the line into the oil housing.

With all this chrome going onto the right side, we didn't want to neglect the left side. So we installed this chrome inner primary cover.

This is one of the new 3.875 Big Bore cast pistons that come with the 103 kit. In order to accommodate the longer stroke, the new pistons are a little bit shorter than the stock pistons. (The pistons are shorter so they won't interfere with the valves or heads.) The kit comes with new piston rings. After checking each ring for proper end gap inside the cylinder, Danny installed the rings on the pistons

When it came to installing the pistons into the Big Bore cylinders, Danny didn't use a ring compressor tool. Instead he inserted the right-side retaining clips in each of the pistons. Then he carefully slid the piston into the bottom of the cylinder, making sure the rings slid in as well. Once all three rings were inside the cylinder, he slid the wristpin through the piston and connecting rod and locked it in place with the left-side retaining clip.

On the left is one of the new 103 cylinder heads, while on the right is the stock cylinder head. One major difference between the new heads and the stock heads is that the new heads feature a slight peak on the deck of the ports. This will help improve airflow, and, as we all know, better airflow means better horsepower.

With the cylinders in position, the heads were installed next and torqued to spec.

The kit comes with a breather assembly. So, before installing the rocker-arm supports, Danny removed the stock breathers and replaced them with the new ones.

We just couldn't resist adding more chrome, so we used Harley's Chrome Hardware Kits for the rocker boxes, outer primary cover, and cam cover.

These new chrome pushrod covers will really add some shine to the right side of the motor.