SFV650: Throttle Position Sensor

Catching up on some posts while Hurricane Arthur goes by the Northeast. I actually did this adjustment a couple of weeks ago.

The Throttle Position Sensor (TPS) on the 2013 Suzuki SFV650 measures and reports the amount of throttle opening to the engine control module in a fuel injected engine. The computer uses this information to make adjustments to the mixture of fuel and air used for combustion. As the throttle is opened, the engine requires more fuel to be added to the mixture to provide more power.

Reports from many Suzuki owners indicate that the TPS is adjusted incorrectly from the factory so that the computer does not begin adding fuel to the mixture until higher in the RPM range. My reason for attempting this adjustment was to make the throttle application smoother while going through the curves. As configured, rolling off the throttle too far while entering the corner results in an abrupt cut-off of fuel and heavy engine braking upsetting the fore/aft balance of the bike.

Items you will need to perform this inspection/adjustment:

• Allen wrenches to remove the bodywork and tank bolts.
• Tank prop stand. I had run the fuel down in the tank until the low fuel warning light was on to avoid any fuel leakage when the tank was propped up to access the TPS.
• “Dealer Mode” switch. Some just jump the dealer mode coupler with a piece of wire.
• Torx 25 security bit for the TPS mounting screw.
• Portable fan to make sure that the bike doesn’t overheat while running the bike in a stationary position while making adjustments to the TPS.

First step is to remove the right side bodywork to access a “Dealer Mode” coupler where you connect a matching plug with an on/off switch. When flipped to the On position, the LCD on the instrument plan displays diagnostic codes and information about the TPS position.

Right side bodywork removed and switch connected:

With the motorcycle running and the Dealer Mode switch turned to the On position, this is what will be seen on the LCD below right under the speedometer readout:

The left side of this photo shows an excerpt from the service manual. All the manual wants to you to do is make sure that the dash is in the center position to properly adjust the TPS. Technically my bike is adjusted properly, but as I rolled on the throttle I found that the dash did not move to the upper position until ≈ 2,000 rpm and idle is at 1,300 ±100 rpm. Others have reported that the TPS was not moving the dash to the upper position until ≈ 3,000 rpm from the factory.

If adjustment is deemed necessary, you will then need to remove the left side bodywork and prop up the fuel tank to get access to the TPS. TPS location:

The TPS is mounted with a single screw with a Torx 25 security head. Loosen the screw slightly so that you can make tiny rotations in the TPS. I rotated the TPS up at idle until it just raised the dash to the upper position on the LCD and then a tiny tap back down to the middle position. Tighten the mounting screw while trying not to move the TPS.

After re-tightening the TPS, check the throttle position where the dash moves to the upper position. Mine is now moving to the upper position at ≈ 1,500 rpm.

I have found that this adjustment had the desired effect for me. I have more room within the throttle rotation to roll on-and off the throttle without having an abrupt cut-off in the fuel mixture. Engine braking is still present, but much more manageable.

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