Jetting for Yamaha YZ 2T bikes

About

This app helps you jet your 2-stroke Yamaha YZ (PW 50, PW 80, YZ 65, YZ 80, YZ 85, YZ 85 LW, YZ 125, YZ 125 X, YZ 250, YZ 250 X) and get the most out of it. From the temperature, altitude, humidity, atmospheric pressure, the oil-to-fuel ratio and the fuel you use it works out the jetting recommended for your exact model. WHY THIS APP - Models from 1995 to 2027, from the PW50 to the YZ250X. - It jets for YOUR fuel: 98 E5, E10, E15, ethanol-free, leaded or oxygenated race fuel, or your own values. - Track mode: main jet, needle, clip, pilot jet and air screw huge and in high contrast, to read in full sun with your helmet on. - Widgets, Lock Screen, Live Activity and Apple Watch: the jetting of the moment without opening the app. - It warns you when the weather changes enough to change the main jet, and when there is a risk of carburettor icing. - Share the jetting with your mechanic with a link or a QR code, and keep your logbook in sync through iCloud. - No ads, no tracking and no account. To get the weather values the app can use the location service and the data connection: it takes your position and altitude, queries the nearest public weather station and brings back its readings. It also works with no GPS and no data, entering the weather by hand. The app has 4 tabs: - Results: the recommended main jet, needle type and clip position, pilot jet and air screw turns for the conditions and the bike you set, plus air density and density altitude. It has fine tuning per circuit —high, mid and low— to match the character of one particular engine. A warning appears under it when there is a risk of carburettor icing. - Conditions: temperature, altitude, pressure and humidity. Type them in, or pull them from the nearest weather station with one tap, without leaving the screen. - Engine: year, region, model, oil mix ratio and fuel. The carburettor is not a choice: the year, region and model determine it. The fuel changes how much petrol the same air asks for, and the screen tells you what that does to the main jet. Underneath sits the mix calculator: it converts between petrol, oil and ratio both ways —in litres, millilitres, US and imperial gallons and ounces— and leaves the ratio set here with one tap. - Logbook: saves each ride with the bike, the fuel, the weather and what the app recommended, so you can note afterwards what you actually fitted and how it went, rated per circuit. Export it to CSV or share a copy to move it to another phone; importing never deletes anything. It syncs between your devices through iCloud. TRACK MODE From Results, the sun button puts the jetting full screen, big, with the screen always on and at full brightness. It shows how much the air density has changed since what you have fitted, how old the data is, your fuel and the icing warning. From there you start a track day and show your mechanic a QR code. ALERTS During a track day the app keeps an eye on the weather and tells you when it changes enough to change the main jet: "Air density has dropped 1.8 % since your last calculation: the main jet goes from 175 to 172." With the hourly forecast it can also tell you ahead of time. Forecast alerts always arrive; the others depend on iOS. Yamaha YZ models that are included: - PW50 from 1995 to 2027. - PW80 from 1995 to 2024. - YZ65 from 2018 to 2027. - YZ80 from 1995 to 2001. - YZ85 from 2002 to 2027. - YZ85LW from 2022 to 2027. - YZ125 from 1995 to 2027. - YZ125X from 2016 to 2027. - YZ250 from 1995 to 2027. - YZ250X from 2016 to 2027.