Those of you who are regular readers of HOT BIKE magazine have no doubt been following our 96-inch Evo build. For those of you not familiar with the project, here’s a quick synopsis: Our goal was to build a strong and reliable, streetable motor without the restraints of using components packaged as a kit. Rather, we wanted to pick and choose parts we felt would work well together once combined to help us reach our goal.
To this point we have a complete bottom end consisting of Harley cases, a JIMS stroker flywheel, a TP Smart Pump (oil pump), a Dave Mackie DM 595 cam, and an S&S; reed valve-style breather.
As we planned, we toyed with the idea of using a set of aftermarket cases. After weighing the ups and downs, we decided to stay with the stock Harley cases in order to keep the serial numbers consistent between the engine and the bike. This could prove to be a big plus when dealing with Johnny Law, or for whenever we decide to sell the bike.
This month, Bob and Eric Bennett of Bennett’s Performance in Signal Hill, CA, will be fitting the JE pistons into a set of Axtell cylinders, then topping them off with a pair of STD heads. The cylinders we chose are a set of Axtell cast-iron pieces (part No. 200-028; MSRP: $915 per pair). We decided to go with cast iron versus aluminum because the cast-iron pieces are extremely stable, and will remain straight and true for many years to come. Axtell manufactures the cylinders utilizing a one-piece cast-iron design, unlike an aluminum cylinder, which has a cast-iron sleeve fitted to it during the manufacturing process.
We will be attaching a pair of flat-top JE Pistons (part No. 161947, included with the Axtell cylinder kit) to the JIMS connecting rods. Based on our calculations and the dimensions of our components, the engine will have a compression ratio of 10.6:1. This should allow us to run the bike on premium pump gas without any problems. The final components we will be installing this month will be a pair of STD Stage IV cast-finished heads (part No. 1990; MSRP: $1,678). Features of the heads include STD’s bathtub-design 1.650-inch exhaust, 1.940-inch Kibble White Black Diamond valves, and Crane premium valvesprings. The highly efficient, ported and polished heads are designed to flow 320 cfm at 28 inches of water (different manufacturers rate these figures differently, so for comparison purposes make sure you are talking apples to apples when looking at different heads).
With the oil-control ring in the piston’s bottom ring groove, Bob used a piston-ring installer to place the second ring (with the dot facing up) in the middle groove. The gap in the ring was placed by the back of the exhaust valve. The top ring was then installed with its gap by the intake valve. This is the coolest area of the piston, so placing the gap here should lead to a long life for the ring.
Eric made sure the manifold lined up just right to ensure that a smooth flow of air would pass to the heads. The bolts were gradually tightened to ensure the manifold would seat properly on both heads.