1985 RZ350

Installing the R1 Gauges - Tach & Speedo

The trick that the original author of the how to worked out really well was how to use the existing funtions of the tach to show information that is needed by the RZ. We'll go step by step for each component starting with the main harness wiring and all wire color functions are listed in the resources page for reference as is a wiring diagram for the original USA RZ. You'll need the following parts:

  • 2000 - 2001 Yamaha R1 gauges (eBay about $125)
  • 2000 - 2001 Yamaha R1 upper wiring harness (eBay about $30)
  • 2000 - 2001 Yamaha R1 thermostat sensor ( for $50)
  • Cherry GS101202 speed sensor from DigiKey ($40 shipped)
  • Misc wire and connectors

The image above shows the R1 upper headlight wiring harness that connects to the R1 gauges, as well as the original R1 motor, thermostat and some other connections.

The harness has to be modified by removing all the parts that aren't used in the conversion. You'll need the main plug for the cluster shown above and the rubber boot to keep out the weather.

You'll also need the thermostat sender plug. Luckily the original wires are easily long enough to reach from the cluster connector to the RZ head.

To remove all the wires not required, peel open the black tape and wrappings to expose the wires in the main trunk. Carefully follow the wires back from the gauge connector and snip them at the furthest point to keep the wires as long as possible.

When you are done you should have a revised harness that looks like the one above, with free wires for the gauge, and the original wires still going to the thermostat sender connection. All the remaining stuff is junk and can be thrown away or go back on eBay??

In order to have the R1 gauge temp readout work you'll need to switch out the existing RZ one which is located in the center of the cylinder head as shown above. Disconnect the single lead to the sensor and zip tie it out of the way as you won't need it any more. You'll need to drain the coolant to replace the sensor. The easiest way to do this is simply remove the two drain bolts in either cylinder. These face out away from the bike on the side of the cylinder sleeve. This won't drain all the coolant but it will get the level lower than where the cylinder temp sensor is located.

In the shot above the original RZ sensor is on the left and an original R1 sensor is on the right. I installed a copper washer between the head and the sensor just to be safe about leaks. It felt like the new sensor had a slightly tapered thread but it went in to the existing cylinder head hole with no problem. There is easily enough room for the top of the sensor. Before going any further now is a good time to refill the coolant and check for any leaks.

At this point you should physically mount the gauges to the bike so that you can make sure all connections are long enough. Plug in the connector to the rear of the cluster with the loose wires hanging out. I used a piece of metal from the new headlights as shown and while I am not especially proud of how it looks, it does the job for now.


The R1 tachometer needs just a single wire connection from the existing flywheel pick-up on the RZ. Since no wire exists from the flywheel to the gauges, you'll have to add one. The easiest way to do this is to find the 3 pin motor connection which is located near the battery/airbox on the right hand side of the bike. Run a new wire from the R1 cluster yellow/black wire and splice in to the white/green wire arrowed in the image above.


The cluster needs two power connections. The first is switched 12V which powers up the gauges when the ignition is turned on. The second is unswitched 12V which keeps a constant source of power to the clock and trip memories even when the ignition is turned off. This has a slight draw on the battery but so far with regular use I have had no voltage issues.

Switched 12V DC: Find one of the many light brown wires on the original RZ cluster and connect it to the light brown wire from the cluster. This is switched DC to the cluster. You can try turning the ignition key after this connection and the gauges should power up. If the tach connection in the previous step is connected the tach will now work.

Unswitched 12V DC: Find one of the many red wires on the RZ. You can get at some of them under the tank, or come right off the red wire to the ignition switch. Splice in to this and connect it to the red/green R1 wire.

Cluster Back Lights: Find the RZ blue/white and connect it to the R1 blue wire. This powers up the back lights when the ignition switch is turned on.


The speedometer on modern sports bikes is digital and is taken by converting pulses as a metal tooth passes by a speed sensor. Since the RZ had a gear driven cable to the front wheel you'll have to make a small bracket to mount the speed sensor near the front sprocket.

Start by removing the sprocket side plastic cover, and remove the chain from the front sprocket so that the area for the bracket is clear. Easiest way to do this is to loosen the rear wheel and push the adjusters all the way to the front. This should allow you to get the chain off. If not you may have to remove the front sprocket. Finally remove the plastic spacer on the shifter rod and keep it safe for later.

The idea is to use the shifter rod and the upper engine mount as two bracket mounting points and bend a metal bar so that there is a mounting surface that is flat against the engine casing. Then make a right angle mount which the sensor will mount to. I found it helpful to oversize the holes to connect the right angle so that you can make smaller adjustments once the sensor is in place. Be sure to use either nylock nuts or split washers to make sure nothing vibrates free.

The final shot shows the finished bracket in place. The sensor can be a little fussy and it needs to be centered on the front sprocket and about 1/8" away from the furthest extent of the teeth. Route the wires back behind the chain and zip tie them down so they don't rub against the chain in the future. Before replacing the plastic side cover I also removed the thickness of the metal bar from the plastic shifter spacer in order to have the same spacing as before the bracket.

I found the original speed sensor wires were long enough to make the following connections:

  • The sensor blue wire goes to ground. Find a fastener on the frame, use a ground lug terminater crimped on to the wire, and bolt it under the fastener.
  • The sensor brown wire goes to the R1 blue/yellow which is the power from the cluster to the sensor.
  • The sensor black wire to the R1 white wire which is the pulse input to the speedo.

The original author also connected the sensor black wire to the RZ white/green wire inside the headlight connections to retain the indicator cancelling feature, but I didn't bother.

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