1985 RZ350

Idiot Lights - R1 Gauges

The previous page noted how to make the main connections to the gauges but the indicators, neutral light, fuel light and oil warning lights now need to be connected.

The neutral light will serve the same function, the fuel light can be disabled or used, the oil warning light that was previously for oil pressure, can be re-used for a low oil warning signal from the 2 stroke oil reservoir, the high beam light is the same, and the single indicator light replaces the left and right indicator lights on the original RZ. Connections are as follows:

  • The RZ sky blue wire connects to the R1 sky blue wire for the neutral indicator.
  • The RZ dark brown wire connects to the R1 dark brown wire for the turn indicator.
  • The RZ dark green wire connects to the R1 dark green wire for the turn indicator.
  • The RZ yellow wire near the headlight connector connects to the R1 yellow wire for the high beam light.

The oil level sensor on the RZ is a weird one. It isn't just a simple open/closed circuit but actually has different resistances at full and low which makes it more difficult to wire up. The light in the cluster illuminates in reverse of what is needed. It lights when there is an open circuit, but turns off when the circuit closes. More on this to come...

The fuel warning light is easy to disable by connecting a 1K ohm resistor to the R1 green/white wire and then connecting this to ground (the frame) somewhere and remaining with the RZ reserve system. Once connected as above, wrap the connection in electrical tape.

This system effectively disables the fuel light forever, however, there is a useful feature in the R1 gauge that starts a trip meter from the point that the fuel warning light is lit. I am working on a system where switching the RZ fuel valve to reserve will illuminate the light and then start the trip function. This is useful for me because my commute is short and sometimes I forget that I switched to reserve the previous night when I get on the bike the next morning. The lit fuel warning light would be a good reminder and also over time I'd get used to how many miles I could do before running out completely...more on this later

If everything worked out well you should have gauges that look sweet, work well, and have more functionality than the previous originals. If you have quicktime you can click the image above which shows the self checks on the gauges when powered up, and the tachometer in action.

Once the gauges were installed and the bike was on the road I noticed the speedo was way off. A little research showed that the R1 takes its reading of a 34 tooth gear on the front sprocket layshaft. I did the math and worked out the differences in rear tire circumference, final gearing, etc... and found that speed displayed was about 44% of the actual speed the bike was travelling partially because the RZ was taking its pick up from a 17 tooth front sprocket. I wanted to double check my math so I will be borrowing a GPS and I'll find a long flat section of road to compare indicated speed vs. GPS indicated speed. Once the ratio is determined for sure I plan to use a Speedo-Healer to get the displayed speed corrected.

The thermostat works well and it is very nice to know the exact temperature on a two stroke. The display will read "Lo" until the coolant reaches 103 degrees F which it does in a few blocks of riding. Typically when the bike is moving consistently the temperatures is between 160 and 180 degrees F, which is consistent with Yamaha's published stats that the thermostat valve opens at 156F and is fully open at 185F. I have had it as high as 208 F when stuck in traffic. Yamaha notes the acceptable range for the R1 is between 104 F - 241F. The warning light will illuminate between 241F and 283F and the display will flash. From 284F upwards it simply shows "HI" but hopefully you'll never see that on a 2 stroke. I don't honestly know where the danger point is for a two stroke....

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