P1 Sensor Upgrade Harness (GREEN Plug) for CX500 Turbos

The P1 Sensor upgrade is highly recommended for any Honda CX500 Turbo. My personal CX500 Turbo arrived after an extensive, frame-off restoration by Honda wizard J.R. Luksik of Clinton Township, Michigan. J.R. did masterful work that included a “quadruple by-pass:” stator, speed sensors, water pump and starter/starter clutch. It ran fantastic over 3,000 rpms.

But, at lower speeds, it was balky, glitchy and a pain to ride smoothly. It had an unreliable idle and was prone to stalling. I sorta hated it at first. But, I did research on the CX500 Turbo Forum and ID’d the issue: a failing Pb Sensor. I replaced the failing Pb sensor with the modern Suzuki replacement mentioned below. That yielded a big improvement! But, I still had some vague lack of perfection in the EFI calibration.

So I replaced the Honda P1 sensor with another Suzuki sensor. This yielded a subtle improvement in overall smoothness and throttle response!

Here are the details: Leo Knijnenburg and Ko Maljaars of the Netherlands did some fabulous research circa 2013 on replacement EFI sensors for the Honda Turbos! They're both members of the Dutch Honda Turbo Motorcycle Club - HFTC Parts Commission. Their incredible research led to a breakthrough that makes these bikes a joy to own and ride.

Details on their P1 (and Pb) Sensor Upgrade research and recommendations is well-documented on the CX500 Turbo Forum. You can review this information via the "KUDOS!" link under "INFO" above.

The Honda P1 sensor simply measures current atmospheric barometric pressure. This signal allows the CPU to automatically compensate for changing weather and changing elevation

In a nutshell: It is easy to replace the Honda P1 Sensor with a modern Suzuki (or Toyota) sensor that has the correct calibration, along with more stable and reliable electronics. This helps restore perfect EFI calibration.

The original Honda sensors were well-calibrated when new. Now, they're old, arthritic, unresponsive, insensitive and deliver erroneous values to the EFI computer. If you have a CX500T, you will definitely benefit from sensor upgrades!

Symptoms of Possible Failing P1 Sensor

* Bike runs poorly whenever there is a sudden weather change
* Bike runs poorly when climbing or descending a mountain pass
* Back-fire on deceleration
* “Over-leanness” off-boost

Features of Turbo Enterprises Sensor Upgrade Harnesses:

* Genuine Sumitomo sealed connector
* Genuine Sumitomo female terminals
* Genuine Sumitomo weather seals
* Correct gauge marine grade wire
* High quality 6.3mm male spade terminals
* Marine grade shrink tubing
* Correct wire colors to match Honda wiring harness
* Longer harness than the Honda sensor harness to facilitate mounting and routing flexibility.
* Non-invasive and reversible without butchery to Honda wiring harness.
* Professional crimps using the correct tools.
* Each harness goes through rigorous quality assurance testing to ensure correct assembly and function.
* Powered-up, load tested and "cycled" using a verified good sensor.
* “Field-tested" on my personal CX500 Turbo.

Each harness ships with complete instructions.

In addition to my upgrade harness, you will need to source a Suzuki (Denso) Sensor.

Review the material regarding "REPLACEMENT SENSOR NOTES" under "INFO" above.

If you buy my sensor upgrade harness, you will need to remove the GREEN connector plug and seal from the end of the Honda P1 sensor assembly. These parts will be transferred over to use on my harness. See the Link above for "Transferring Honda Plug and Seal" details.

Note: My Pb and P1 Upgrade Harnesses are similar but different. Each connects to the Suzuki or Toyota sensors mentioned above, but the harness lengths and wire colors are different, so they are not interchangeable.

REMINDER: the Honda GREEN plug, Honda seal and Suzuki sensor are NOT INCLUDED.

NOTE: This harness is for CX500 Turbos only. CX650 Turbos do not have a P1 Sensor.