At Fuel Moto, we continue to push the performance limits of Harley-Davidson’s Milwaukee-Eight platform. In our latest round of testing, we revisited one of our most popular configurations—the Milwaukee Eight 117 Stage III Big Bore setup—designed for riders who crave torque and real-world rideability.
For this test, we installed the FM 117 big bore kit featuring 4.125-inch cylinders. However, instead of our standard high-compression build, we opted for a lower compression 10.75:1 piston. This setup allowed us to pair the kit with one of our proven bolt-in camshafts—the Wood WM8-222. This approach gives riders an easy-to-install upgrade with impressive performance, even while keeping stock heads and throttle body.
To complete the combination, the test bike used:
- Stock fuel injectors (which operated right at their limit)
- Jackpot M8 2/1/2 head pipe
- S&S MK45 slip-on mufflers
- Tuned with Dynojet Power Vision
Aside from the big bore pistons and cylinders, this build was nearly identical to our previous 107 M8 camshaft test. The difference? An added 10 cubic inches and a slight bump in compression. The result? A significant torque increase and a much broader powerband, making this one of the best bolt-in style Stage III upgrades available.
More Stage III Testing
In another variation of our Milwaukee Eight 117 Stage III Big Bore testing, we ran the same FM 117 kit using a Wood WM8-22X camshaft and an HPI throttle body, again keeping stock cylinder heads. This combo delivered exceptional low-end torque, ideal for real-world riding, especially for touring models loaded up with gear.
For riders seeking a powerful, reliable upgrade without sacrificing rideability or needing extreme mods, the 117 Stage III kit is a proven winner.
Looking to build your own Milwaukee-Eight 117 big bore setup? Contact Fuel Moto for expert guidance, tuning support, and everything you need to bring your build to life.