Jetting for Yamaha YZ 2T bikes

Name: Jetting for Yamaha YZ 2T bikes
Price: 3.99 USD
Rating: 5 (3 reviews)
Author: ISEnet

YZ65, YZ85, YZ125, YZ250 & PW

$3.99 · Designed for iPad. Not verified for macOS.

3 Ratings
Age Rating

4+
Years
Chart

#194
Sports
Developer

ISEnet
Language

EN
+ 6 More
Size

5.4
MB

Jetting for 2-stroke Yamaha YZ and PW from 1995 to 2027, for your fuel. Track mode, widgets, Live Activity, Apple Watch and alerts when the weather changes. 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.

Ratings & Reviews

5.0

out of 5

3 Ratings

Works great
10/09/2016
Extreme sky guy
I tried this setup and it worked great! Some may say that it doesn't work because the bike won't idle, but they don't understand that this is how bikes are race tuned - it is to help the bike slow down faster with engine braking. If you have a doubt, adjust it first and grab the throttle halfway - it will lift the front end well before it hits the powerband. I went to sand mountain (Utah - 700 ft high dune) and the bike was still grabbing more power as I was flying up the dune in 3rd gear 1/2 to wide open throttle. Highly recommended.

Developer Response
Sorry for the late reply, and thanks for the detailed report from Sand Mountain. Version 2.4, released in August 2026, readjusted the main jet curve for better response with altitude, and version 2.6 adds a mix calculator. We've changed how we handle reviews, so every one now gets an answer.
Works great
10/09/2016
Extreme sky guy

I tried this setup and it worked great! Some may say that it doesn't work because the bike won't idle, but they don't understand that this is how bikes are race tuned - it is to help the bike slow down faster with engine braking. If you have a doubt, adjust it first and grab the throttle halfway - it will lift the front end well before it hits the powerband. I went to sand mountain (Utah - 700 ft high dune) and the bike was still grabbing more power as I was flying up the dune in 3rd gear 1/2 to wide open throttle. Highly recommended.
Developer Response Oct 1
Sorry for the late reply, and thanks for the detailed report from Sand Mountain. Version 2.4, released in August 2026, readjusted the main jet curve for better response with altitude, and version 2.6 adds a mix calculator. We've changed how we handle reviews, so every one now gets an answer.
Spot on…!!!
01/28/2023
DC Equipment
I use this app for all my two strokes. I live in Reno Nevada and ride Nor Cal MX tracks often. The jetting recommendations is always spot on for me. More riding and less jet changes. 😎

Developer Response
Sorry for the late reply, and thank you. Version 2.6, released in August 2026, adds a mix calculator in the Engine tab, and recent updates brought models up to 2027, a ride log with what the app recommended and what you fitted, and better response with altitude. We've changed how we look after reviews, so every one now gets an answer.
Spot on…!!!
01/28/2023
DC Equipment

I use this app for all my two strokes. I live in Reno Nevada and ride Nor Cal MX tracks often. The jetting recommendations is always spot on for me. More riding and less jet changes. 😎
Developer Response Oct 1
Sorry for the late reply, and thank you. Version 2.6, released in August 2026, adds a mix calculator in the Engine tab, and recent updates brought models up to 2027, a ride log with what the app recommended and what you fitted, and better response with altitude. We've changed how we look after reviews, so every one now gets an answer.
Update Your App
05/09/2019
Bishnu S.
This app is still suggesting the 2006 and older needle jet N3EJ as standard for just about all temps/ elevations for a newer YZ250 including warm climate close to sea level. Yamaha changed to the N3EW needle in 2007 as it improved bottom and mid range. I assumed I needed to go with the leaner N3EJ needle as per this apps suggestion so I purchased one. It is not an improvement. I did plug in 2017 as the year of my bike. Take some time and get everything correct and current for one of the most common 2 strokes available. The other settings seem accurate. Also not a huge deal but a nice touch would be to list the YZ250X as a selectable option. I get that the jetting is the same as a YZ250 but at least list it.

Developer Response
Sorry for taking so long to reply, and for the needle you bought for nothing. You were right to ask us to update. Version 2.4, released in August 2026, revised the jetting against Yamaha's official service manuals, correcting needle type, clip position and air screw on several 2021 to 2024 models, and the YZ250X now appears as its own model. The 2017 YZ250 needle isn't among those corrections, so we've noted it to review; any details you can send to mobile@isenet.es will help. We've changed how we look after reviews and emails, and every one now gets a reply.
Update Your App
05/09/2019
Bishnu S.

This app is still suggesting the 2006 and older needle jet N3EJ as standard for just about all temps/ elevations for a newer YZ250 including warm climate close to sea level. Yamaha changed to the N3EW needle in 2007 as it improved bottom and mid range. I assumed I needed to go with the leaner N3EJ needle as per this apps suggestion so I purchased one. It is not an improvement. I did plug in 2017 as the year of my bike. Take some time and get everything correct and current for one of the most common 2 strokes available. The other settings seem accurate. Also not a huge deal but a nice touch would be to list the YZ250X as a selectable option. I get that the jetting is the same as a YZ250 but at least list it.
Developer Response Oct 1
Sorry for taking so long to reply, and for the needle you bought for nothing. You were right to ask us to update. Version 2.4, released in August 2026, revised the jetting against Yamaha's official service manuals, correcting needle type, clip position and air screw on several 2021 to 2024 models, and the YZ250X now appears as its own model. The 2017 YZ250 needle isn't among those corrections, so we've noted it to review; any details you can send to mobile@isenet.es will help. We've changed how we look after reviews and emails, and every one now gets a reply.
Ok setting suggestions
05/02/2023
allthenicknamesaretaken$&$$
But the pilot jet recommendations are far off, ie 5000 to 10,000 asl only recommends a turn out on a/s when I’ve found 2 sizes down on pilot is necessary, seems to recommend rich settings here. It’s difficult to input elevation with the keyboard being in the way.

Developer Response
Hello, the issue with the elevation input is solved since last update.In the case of the pilot jet recommendation, our model tries to enrich at low in order to be safe (most seizes are after WOT and suddenly close throttle), and that let us put a one size leaner main jet to maximize power.
Ok setting suggestions
05/02/2023
allthenicknamesaretaken$&$$

But the pilot jet recommendations are far off, ie 5000 to 10,000 asl only recommends a turn out on a/s when I’ve found 2 sizes down on pilot is necessary, seems to recommend rich settings here. It’s difficult to input elevation with the keyboard being in the way.
Developer Response 10/20/2023
Hello, the issue with the elevation input is solved since last update.In the case of the pilot jet recommendation, our model tries to enrich at low in order to be safe (most seizes are after WOT and suddenly close throttle), and that let us put a one size leaner main jet to maximize power.

Track mode, your fuel, widgets, Apple Watch, alerts and iCloud. - Fuel: pick 98 E5, E10, E15, ethanol-free, leaded or oxygenated race fuel, or your own values, and the jetting is corrected for it. The Engine tab tells you what it does to the main jet. - Carburettor icing warning, from the temperature and humidity. - Track mode: the jetting full screen, huge and in high contrast, always on and at full brightness. Start a track day from there and show your mechanic a QR code. - Widgets, Lock Screen, Live Activity and Apple Watch, with complications. - Alerts when the weather changes enough to change the main jet. - Share the jetting with your mechanic by link, QR code or file. - Logbook and settings sync through iCloud, and the logbook now records the fuel. - Dark mode, a redesigned More Apps screen, and location that works on iPads without GPS. - Fixes: the region no longer changes when you change the phone's language, changing bike no longer resets your oil mix, and the nearest part is now chosen correctly at the ends of each list. IN PREVIOUS VERSIONS - 2.6: mix calculator inside Engine, and a new icon. - 2.5: Logbook tab, and the weather station inside Conditions. - 2.4: bikes updated through 2027, with the YZ85LW as a new model. This version requires iOS 15 or later.

Version 2.7 4h ago

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Information

Seller: Ingenieria del Software ISEnet S.L.
Size: 5.4 MB
Category: Sports
Compatibility: Requires iOS 15.0 or later.

iPhone
Requires iOS 15.0 or later.

iPad
Requires iPadOS 15.0 or later.

iPod touch
Requires iOS 15.0 or later.

Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later.

Apple Vision
Requires visionOS 1.0 or later.

Apple Watch
Requires watchOS 10.0 or later.
Languages: English and 6 more

English, French, German, Italian, Portuguese, Russian, Spanish
Age Rating: 4+

4+

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