CNC-machined aluminum Nikasil cylinder for durability and precision
Balanced crankshaft and MZ65 style expansion chamber for improved reliability
Universal-fit pipes and CNC piston port for easy installation and tuning
High-performance 8.9 HP output for increased speed and acceleration
Includes complete hardware and assembly for straightforward setup
Summarized by Shop
**Built-To-Order. Please email and confirm delivery ETA before ordering**
The Most Powerful engine kit on the market, the Menace85 SS bolt-on kit! 8.3HP!!
Upgrades:
52mm Bore x 40mm Stroke
CNC Smolik Head
Balanced Crank
"MZ65 Style" Expansion Chamber Pipe
PHBG 21mm Carburetor
CNC Piston Port Intake
Standard Parts:
36t Sprocket and Har
Displacement
85 cc
Bore
52 mm
Stroke
40 mm
Cylinder Material
Aluminum Nikasil
HP
8.9 HP
Torque
5.5–6 ft-lbs
Peak RPM
10,500–11,500
Top Speed
55 mph
Oil Ratio
32:1
Carburetor
PHBG 21 mm
Chain
415, 36T sprocket
Summarized by Shop
4.9
39 ratings
5
4
3
2
1
Quality product. Performes great. Definitely recommend this product and company.
Larry · 10 days ago
Good motor just been waiting on my exhaust gasket and bolts I repurchase but motor great
T
Tanner · June 1, 2026
Fun project, great service. The Smolik's are super active in the motorized bike community, and respond to questions. I had my ported motor kit in about a week, and the only reason it isn't running yet, is I need some parts to make it work with my bike, absolutely not their fault. I checked the engine over, and it was clean of shavings, squish gap was excellent. I will caution, because it caused me some confusion, they started shipping with one base gasket installed, rather than 2, and I don't think they changed the site to reflect that, but I turned to the Internet to research, and sure enough, the question was asked, and Kurt confirmed that the gen 3 only needs one base gasket. Thank you guys for what you do, and I look forward to a long working relationship with you.