EPA-Legal Harley-Davidson 103ci Hop-Up

Afterwards, the top of the piston was numbered with a marker to show where the ring gaps were to ensure a good seal.

To get the pistons into the cylinders, Brian coated them with assembly lube, then used a ring compressor to hold the rings in place as he installed the piston.

Before the new cylinders were installed, he replaced the O-rings for the case port shown here.

Then Brian installed the new pistons and cylinders to the rods, and then installed the heads.

Even though this is a kit install, Brian checked valve clearance with a small amount of clay on the top of the piston, rotated the motor by hand, then measured the marks left in the clay. All of the valves were good and within spec.

Next, the rockers, pushrod tubes, and rods were installed. Brian re-adjusted the pushrods, then installed the rocker boxes.

This kit came with a new set of catalyst mufflers; Brian removed the old mufflers and replaced them with the new catalyst mufflers.

A Stage I air filter kit is included in this kit, shown here with breathers and backing plate.

With the Stage I air filter you still use the stock cover; however, if you check the P&A catalog, there are a few different options to choose from.

Lastly, the gas tank was bolted back on the bike, and all the wires were reconnected (including the battery).

After completing a required ECM calibration we were off for a few test miles. After Brian returned he checked oil temp and levels. Over the next few days we put just over 400 miles on it before we ran it on the dyno.

The bike was placed back on the dyno, and the numbers were 79.62 hp and 97.04 lb-ft of torque. The numbers were not huge, but the torque was where we wanted it, right at the mid-range as we pulled through Third gear into Fourth, and with a passenger on the bike we still had plenty of pull and acceleration. The whole job was done in less than eight hours, we were on the road the same day, and we have a 50 state-legal EPA bike that still has the factory warranty.