Calculators
Two-stroke Premix Ratio Calculator
Required Oil
--- mL
Master Your Two-Stroke Premix Ratios
Correct lubrication is the lifeline of any 2-stroke engine. Whether you are running a high-performance motocross bike at 32:1 or a modern weed eater at 50:1, precision matters. Using too much oil (rich) can lead to carbon buildup, fouled spark plugs, and clogged exhaust ports. Using too little oil (lean) risks catastrophic engine seizure. This calculator handles the math for both metric and imperial units, ensuring your gas-to-oil mixture is perfect every time you hit the track or the trail.
Port Timing Calculator
Port Duration
---°
Opening/Closing: ---° BTDC/ATDC
Optimize Two-Stroke Port Duration
Port timing determines your engine's powerband characteristics. By calculating the exact degrees of crank rotation that a port remains open, you can tune for low-end torque or high-RPM peak horsepower. This tool uses trigonometry to account for rod-to-stroke ratios, providing the opening and closing angles relative to Top Dead Center (TDC). Tuning exhaust port duration is critical for coordinating with expansion chamber resonance, while transfer port timing dictates the scavenging efficiency of the cylinder.
Compression Ratio Calculator
--- : 1 (Geometric)
--- : 1 (Effective)
Geometric vs. Effective Compression
In a two-stroke engine, "Geometric Compression" is only half the story. Because the exhaust port is open during the initial part of the upward stroke, no compression occurs until the piston closes the port crown. Our "Effective" (or Trapped) Compression Ratio calculator accounts for this port height, giving you the real-world pressure ratio. Use this to determine octane requirements and avoid detonation. Balancing high compression for power against the heat generated is the key to a reliable, high-performance two-stroke build.
Simple Crank Balance
Target Weight
--- g
Crankshaft Balancing & Vibration Control
Single-cylinder engines are inherently unbalanced. The "Balance Factor" is the percentage of the reciprocating weight (piston, rings, small end of rod) that is countered by the crankshaft webs. A 50% factor typically splits vibration between vertical and horizontal planes. High-RPM engines often favor higher factors to keep the chassis smooth at speed. This calculator helps you determine the exact weight to add or remove from your crank webs to achieve your target balance factor, reducing bearing wear and rider fatigue.
Advanced Balance Shaft Designer
Single Cylinder 2-Stroke Counterbalance Design
Engine Specifications
Component Masses
Balance Requirement
Shaft Geometry Designer
Advanced Balance Shaft & Harmonic Engineering
When a crankshaft is balanced to a 50% factor, it creates a rotating unbalance that counters 100% of the vertical reciprocating force, but leaves a horizontal force of equal magnitude. The counter-rotating balance shaft is designed to precisely cancel this horizontal force. This designer allows you to engineer the specific geometry—outer radius, depth, and sector angle—of the balance weights. By matching the "Shaft Target Moment" to your engine's specific reciprocating mass and stroke, you can virtually eliminate primary vibrations, resulting in a smooth, high-revving engine that is easier on both the chassis and the rider.
