2003 Harley Davidson Twin Cam Engine - Cylinder Head

After putting the MLS gaskets on the top of the cylinders, the heads were installed and torqued in increments of 25, 35, and finally 45 lb-ft.
After putting the MLS gaskets on the top of the cylinders, the heads were installed and to
We would reuse the H-D rocker boxes and arms but there was some interference once we placed the rocker box over the valvesprings.
We would reuse the H-D rocker boxes and arms but there was some interference once we place
Therefore, we had to open up the holes in the rocker box before proceeding.

Then it was time to install the rocker-arm assemblies into the rocker box.
Adjustable pushrods were used. We slid them through the pushrod tubes and through the heads. Dan decided to marked them with white paint.
Adjustable pushrods were used. We slid them through the pushrod tubes and through the head
The pushrods were adjusted with two wrenches. It's important to let the lifters bleed down to ensure proper adjustment before moving onto the other pushrods.
The pushrods were adjusted with two wrenches. It's important to let the lifters bleed down

Once all four pushrods were adjusted, the top rocker box was installed.
On the left is the new Kryakyn throttle body, with the OEM unit on the right. The Kryakyn unit is a high-volume unit that flows much more air than the stock throttle body.
On the left is the new Kryakyn throttle body, with the OEM unit on the right. The Kryakyn
Now we just needed a chassis to throw the motor in so we could get in some break-in miles before putting the package to the ultimate test: the dynamometer.
Now we just needed a chassis to throw the motor in so we could get in some break-in miles

We took the custom bagger the motor was in and rode it over to Geoff Gaites' Cycledoctor shop for dyno tuning. After dialing in the ignition and the EFI map, the 95-inch motor produced a whopping 120.72 hp with 108.07 lb-ft of torque. But those numbers don't tell the whole story. The chart shows usable street power; at 3K rpm the motor pulled more than 90 lb-ft, rising to peak torque at 5K before a slight leveling-off. This motor has no problem pulling the bagger's front wheel off the ground.