HOW TO: Excelsior motor rebuild Part 2: Reassembly
Once the motor parts had been repaired/replaced/rebuilt, it was time to assemble the parts, align and adjust things, then get on the road.
The cast iron pistons and rings were measured and were still fitting the bore. An advantage to CI pistons is that they don’t wear quickly like aluminum pistons do. They also are thermally matched to the bore, so they both grow at the same rate as the temperature rises. This also greatly reduces the chances of pistons seizing.
Lots of holes in the pistons, especially in the front one. I thought that maybe they had been modified to be lighter by a previous owner, but the factory photos in the parts manual show all these holes too.
New circlips, and check out the size of the rings! No oil control rings, this is a constant-loss oiling system. The oil goes past these rings, then gets burned up and goes out the exhaust valve, then through the muffler. (the muffler has no rust after all these years…)
Both pistons and barrels installed. Getting ready to mount in the frame.
Motor into frame, then add the Schebler carb, intake valve cages, oil pump and copper lines, timing cover & pushrods, exhaust, primary drive, lots of linkages,set the magneto timing, etc etc etc.
On the road for a test drive, with 30 pounds of tools on the rear rack:
The reassembly and test ride were a whirlwind of 2 days and nights. But I was glad that no major issues came up, and the bike did several hundred miles the following weekend, with just a few nuts and bolts coming a bit loose due to vibration.