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CJR RTD4 Datalogging Guide

Datalogging with the CJR Performance RTD4

Your CJR Performance RTD4 allows you to record ECU data directly through the HP Tuners TDN (Tune Delivery Network) app on your smartphone. Datalogs allow CJR Performance to review how your motorcycle is running under real-world conditions and make tune revisions when necessary.

Depending on the motorcycle and tuning requirements, additional equipment such as a AEM wideband gauge/controller + O2 sensor may be required for accurate fuel/AFR adjustments.

Before Starting a Datalog

Before recording, make sure:

  • The correct CJR tune is currently flashed to the motorcycle.
  • Your RTD4 is connected to the motorcycle and paired with the TDN app.
  • The motorcycle is fully warmed up unless you are specifically logging a cold-start or warm-up issue.
  • You have a safe, controlled area to perform the requested datalog.
  • If a wideband is required, verify it is connected and reading properly.

For most tuning logs, we want the engine at normal operating temperature before beginning.

Recommended Datalog

For fuel and general tune refinement, CJR will typically request controlled throttle runs at:

25% → 50% → 75% → 100% throttle

These can normally be recorded in the same datalog. The goal is to provide smooth, consistent data through as much of the RPM range as possible.

Rather than quickly opening and closing the throttle, try to establish the requested throttle position and hold it steady while RPM increases.

Example

For a 25% throttle run:

  1. Start around 2,000 RPM in a suitable gear.
  2. Smoothly open the throttle to approximately 25%.
  3. Hold the throttle as steady as possible.
  4. Allow the engine to accelerate through as much of the usable RPM range as possible.
  5. Release the throttle and prepare for the next run.

Repeat the process at 50%, 75%, and 100% throttle.

Lower-throttle runs may work better in 1st or 2nd gear, while higher-throttle runs may require a higher gear depending on the motorcycle, available space, and riding conditions.

Every motorcycle is different. If the bike will not pull through the desired RPM range at a certain throttle position, use a different gear rather than forcing the engine to lug.

Throttle Position

Some Honda ECUs may report throttle position as an angle/degrees rather than a simple 0–100% value.

If this applies to your motorcycle, first determine the maximum throttle value shown in the datalog. For example, if wide-open throttle displays approximately 74°, your approximate targets would be:

  • 25%: 18.5°
  • 50%: 37°
  • 75%: 55.5°
  • 100%: 74°

Don't worry about holding the throttle perfectly. Smooth and consistent throttle input is more important. Staying within approximately 5° of the requested position generally still provides useful data.

What Makes a Good Datalog?

The most useful logs have:

  • Smooth, controlled throttle input
  • Steady throttle position during each pull
  • A wide RPM range
  • Fully warmed engine
  • Clearly separated 25%, 50%, 75%, and 100% runs
  • No unnecessary rapid throttle changes
  • Proper wideband AFR data when requested

The longer you can safely hold a consistent throttle position through the RPM range, the easier it is for us to analyze and accurately adjust the tune.


Sending Your Datalog to CJR

Once your requested runs are complete:

  1. Stop and save the datalog in the TDN app.
  2. Make sure your phone has an internet connection so the log can upload/sync.
  3. Send the completed datalog back to CJR Performance through TDN.
  4. If possible, include a short description of the log or what you were testing.

CJR will review the data and, when necessary, make adjustments to your tune.

Once your revised tune is ready, it can be delivered remotely through TDN. You can then flash the updated tune from your smartphone and repeat the datalogging process if additional refinement is required.

Important Safety Notice

Only perform datalogging where it is safe and legal to do so. Do not attempt to watch your phone, gauges, or RTD4 while riding. Your attention should remain on safely operating the motorcycle.

For high-speed or wide-open-throttle testing, we strongly recommend performing the datalog on a closed course, racetrack, or dyno.



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