Two Stroke Calculator SoftwareClick here to download the Word document to fill in the needed data to then send to me. The following are spreadsheets for different aspects of 2 stroke design/modification. They come in two versions - for Microsoft Excel, and for Libre Office. So you can request either version. If you don't have Excel or have a version of Excel that doesn't work with macros then you can buy Microsoft Office 365 for $70, or buy this 2021 version from TechSpot for $40, or use Libre Office for free. Click here to get a free download of Libre Office. Some helpful videos of mine: Using Excel Spreadsheets, My Spreadsheets Overview Download my free calculators spreadsheet to check your computers ability to use spreadsheets. Also, you don't even need Excel on your computer/phone. Just sign up for your free OneDrive Personal Cloud Storage then click "Create Free Account". Then upload the Excel files and then click on any one to use it on-line. Unfortunately it won't let you use macros but they are not essential in most cases, just time savers. Each programs usage instructions tells how to do manual entry if you can't use macros. If your spreadsheet program can use macros but nothing happens when you click any of my programs macro button then let me know and I'll go to the internet cyber and recopy it using their more recent version of Excel and then send it to you. Also you can use iCloud Numbers (but without macro ability). Expansion Chamber Analysis & Design This is a complex return wave simulator that allows you to analyze an existing pipe or design your own for the desired powerband and top RPM. Max RPM allowed is 15,000. read more Expansion Chamber Analysis & Design for high RPM mini engines This allows you to analyze an existing pipe or design your own for the desired powerband and top RPM. The max RPM allowed is 48,000. read more Porting Calculator Calculate the amount of exhaust/transfer overlap to see if you need to change the port height for best power. This is not a rehash of the old outdated port time*area formulas but rather it relies on the true blowdown time (the time it takes for the exhaust pulse to go to zero pressure). read more Jetting Calculator Calculate your carburetors richness thru the whole throttle range to know what to change (pilot jet, slide cutaway, needle, needle jet, and main jet) for perfect air/fuel ratio throughout. For Mikuni, Keihin, Dellorto, and others. read more Squish Velocity Calculate the cold and hot squish velocity at the input piston/head clearance (inner and outer) and squish band width. Too little and you are losing power. Too much and you are risking detonation. read more Crank Balance Calculate the right size and placement of counter-balance holes in the crank wheels for less vibration. This calculates all involved forces every 15 degrees of crank movement. This is the best program available. read more Yamaha Energy Induction System (boost bottle) Calculate the correct dimensions for the bottle to resonate right at the RPM range before the engine gets "on the pipe" which is when there is a bad power dip which the bottle counters. read more 2 Stroke Fuel/Oil Ratio Calculator Calculate the needed fuel/oil ratio dependant on your oil, type of riding, max RPM, and type of cylinder cooling. This uses my formula that goes mostly by the oils viscosity and viscosity index and estimated upper cylinder temperature. read more Carb Size Calculator Calculate the needed carb size for street/trail or racing according to cylinder bore, RPM, and cranking PSI. This helps you not buy too large a carburetor and also helps you evaluate whether or not you should change the engine compression. read more  Author: Michael Forrest Email: 19jaguar75@gmail.com USA tel #: 305-572-5327 (this is a forwarding # to me in Ecuador so I pay for the call so please make your call short and sweet. thanks) Keihin Needle Decoder: This page explains the spreadsheet and allows its download. Needle Clearance Analyzer: This page explains this spreadsheet that helps you find out if your neede/jet clearance is way off. The Deck Calc spreadsheet. A normal deck measurement is not true because you measure it when the engine is cold. When the engine is running the con rod elongates more than the cylinder does due to heat. That makes the piston higher at TDC. My calculator lets you use the measurement of the ring marking on the cylinder which is true for the engine when it's hot. Using that and a couple other measurements plugged in to my calculator you can arrive at a true deck distance which you can plug into an on-line port duration calculator to find the "hot" port durations. link |