Engine Builder Assistant

⚙️ Engine Build Assistant

Engine Build Assistant is a precision calculator and simulation app made for motorcycle engine builders, tuners, mechanics, and enthusiasts working on single-cylinder underbone, scooter, moped, and street-drag engines.

Designed for high-performance 4-stroke single-piston builds, this app helps you plan, calculate, compare, and document your engine setup before spending money on parts or machine shop work. Whether you are building a daily street setup, a high-compression racing engine, a long-stroke drag build, or a reliable scooter CVT combination, Engine Build Assistant gives you a smarter way to work with numbers.

This app acts as your digital workshop companion, helping you understand how changes in bore, stroke, rod length, gasket thickness, piston deck clearance, combustion chamber volume, valve sizing, gearing, fuel injector flow, and transmission setup affect your final build.

🔧 Key Features

• Engine displacement calculator

Calculate engine size using bore and stroke values for single-cylinder motorcycle engines.

• Static and dynamic compression ratio

Estimate SCR and DCR using chamber volume, gasket thickness, deck clearance, piston dome or dish volume, and intake valve closing timing.

• Spacer and long-stroke setup calculator

Find the needed base spacer thickness when using longer rods, offset crank pins, or stroker crankshaft setups.

• Fuel injector and fuel flow sizing

Estimate required injector flow in cc/min based on target horsepower, fuel type, duty cycle, and tuning overhead.

• Valve and cylinder head sizing

Check intake and exhaust valve area, port-mouth diameter, gas speed, and breathing headroom for your engine displacement and target RPM.

• Cam and valve timing support

Use cam timing values such as intake valve closing to better understand dynamic compression and powerband behavior.

• Gear, sprocket, and speed calculations

Simulate manual gear ratios, front and rear sprocket changes, tire size, target RPM, and estimated top speed.

• CVT scooter setup tools

Plan scooter transmission combinations using roller weight, pulley setup, belt width, clutch and center spring behavior, and final drive ratio.

• Tire size and wheel circumference calculator

Convert tire width, aspect ratio, and rim size into usable drive and speed calculations.

• Drag and performance estimates

Estimate acceleration and speed potential using bike weight, rider weight, gearing, power, and setup data.

• Valve shim calculator

Find the correct replacement shim size using measured clearance, target clearance, and current shim thickness.

• Build logs and saved setups

Keep records of your custom builds, engine specs, clearances, gearing, and tuning notes for future reference.

🏍️ Built for Popular Motorcycle Platforms

Engine Build Assistant is useful for many single-cylinder motorcycles and scooters including Honda RS150R, Sonic 150R, GTR150, Winner, Wave 125i, Wave 110i, BeAT, Click 125/150/160, ADV 150/160, Yamaha Sniper 150, Sniper 155 VVA, Mio, NMAX, Aerox, Suzuki Raider R150, Raider R150Fi, Smash, Step, and other similar 4-stroke single-cylinder engines.

⚡ TUNE Tab Coming Soon

The upcoming TUNE section is being developed to support advanced simulation for ignition maps, air-fuel ratio planning, calibration references, and professional tuning workflows. Current tuning-related functions are intended for simulation, learning, and planning purposes only.

⚠️ Important Disclaimer

Engine Build Assistant is a calculation and reference guide. Results are theoretical estimates and should not replace professional inspection, actual measurement, dyno testing, ECU tuning, or experienced mechanical judgment. No two engines are exactly the same. Always verify clearances, tolerances, compression, fuel delivery, and tuning safety before running any modified engine.

Engine Build Assistant helps you build smarter, plan better, and reduce guesswork in your motorcycle engine projects.