We're Back in the Shop Again! (We have a new project).

We have a UL motor for check out -repairs that a Gentleman recently brought in. He’s rebuilding the bike and wanted the motor checked out and some upgrades performed.. We are going to upgrade the oil pump for increased flow, and add some coatings to those areas in the combustion chamber to help minimize heat absorption, among other things

the motor had been redone sometime in the past, but wanted to see what condition it was in while he had the bike apart. So, we opened ‘er up, and found some interesting things.

Most evident was that the engine seemed to be starved for oil. The cylinders and pistonsboth showed scuffing. The front baffle was still in place and modern oil rings had been installed. Originally, flatheads were equipped with 2 compression and one pseudo oil ring on the rear piston, and 3 compression rings on the front cylinder. The No oil ring and the baffles were supposed to meter what oil got to the front cylinder to prevent wear and at the same time over oiling. I have my views on the over oiling thing, but I’ve preached about them elsewhere.

As you can see, the front baffles are still in place. We’re going to remove them.

We’ll also rework the oil pump, which is the type with the larger body, for increased flow by adding a second set of vanes to the rotor. We will also disable the centrifugal bypass valve in the rotor so that the pump does not by pass oil at low speeds, rather provides full flow at all times. We also found that the pump had been installed with the wrong pump body gasket

Observe the slot in the gasket that connects two holes on the right side of the picture. This is to bypass oil from the bigend feed to the timing chest.

Look at the gasket picture for the slot between two holes on the right side of the picture. This gasket was intended for late “G” motors on 3 wheelers. Harley stuck to their over oiling theories and included this cut to cut down on oil to the big end-cylinders at lower speeds. the cut in the gasket would divert oil directly to the timing chest/return pump so “too much” oil wouldn’t go to the bigend/cylinders. So, this poor motor had the gasket “bypass” as well as the centrifugal bypass diverting oil from the cylinders! No wonder things looked a little “hot” in that neighborhood.

As a result of this, we’ll be fitting new pistons, and we’ll have a anti friction coating applied to them.

We’ll have more posts on this engine as time goes on, I’m playing catchup with my postings, as currently we have a lot of work and photos done, but haven’t had time to get them on the web. Stay tuned…