Sensor location is critical to achieving optimal tuning results. The accuracy of the calibration is only as good as the quality of the data the sensors provide.
Most exhaust systems come with pre-installed O2 bungs positioned primarily for aesthetics, typically on the backside of the pipe. Unfortunately, this placement often results in the sensor being poorly exposed to exhaust flow—especially at low speeds and part-throttle conditions when the pipe is not fully saturated with gas. This issue is frequently worsened by exhaust towers or extensions that pull the sensor even further out of the main exhaust stream, leading to inconsistent readings and poor low-speed performance.
To correct this, at Cycledoctor the sensors are temporarily installed to the front side (outside radius) of each exhaust pipe, where they are exposed to the highest percentage of exhaust gas flow. Extensive testing has consistently validated this approach, resulting in significantly improved throttle response, smoother operation, and excellent overall performance. However, on exhaust systems without full-coverage heat shields, this placement sometimes makes the access hole visible.
Precision tuning requires sampling where the exhaust flow is most concentrated. I utilize a specialized sampling block positioned on the outer radius of the pipe, leveraging fluid dynamics to capture the high-density gas stream as it banks through the exhaust path. This ensures a pure, undiluted sample for the NTK wide-band sensor, even at lower speeds where gas flow is less uniform. The result is a more accurate calibration across the entire RPM range, finished with a professional, low-profile seal.
Below are examples of what it looks like during various stages of the process.
Here is the final result of a bike with no heat shields:
Sampling exhaust gas accurately is only one piece of the puzzle. I pair this hardware with TTS MasterTune software, which samples data at a significantly higher rate than any other product on the market. This high-speed resolution allows me to see and correct engine behaviors other tuners simply miss. Experience a smoother, more refined calibration that maximizes your bike’s true potential.
