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Discussion Starter · #1 ·
Hey all, I’ve got an ‘02 R1 with an issue that I can’t quite figure out. It started with my bike starting up and running fine one day, but once the temperature gauge was able to display a reading, the idle speed started slowing down and down until it stalled out. This would happen consistently and would repeat the exact same results every time I would cold start it. Eventually I ended up turning the idle speed screw in a bit to allow for a proper idle so that it would be rideable. Since I did that, the bike is feeling noticeably slower than it used to, so I would really like to solve this issue.

My suspicion is the throttle position sensor, considering that the ‘04-06 R1s had a recall for the tps, and the symptoms listed in the recall letter they sent out are identical to mine. The problem is that one, my bike isn’t an 04-06 so I can’t just send it to a dealership for them to fix it at no charge, and two, I did some diagnostic testing on the tps and compared the results to the specs in the manual. The results were confusing and pretty much inconclusive, so this is why I need some help. The data I took is down below, and they were tested as specified in the manual:

Resistance readings (colors indicate which wire the probes were on in the tps plug):
  • Yellow to black (throttle closed): 0.735 kΩ - in spec
  • Yellow to black (throttle open): 3.72 kΩ - in spec
  • Blue to black (throttle closed): 4.70 kΩ - in spec
  • Blue to black (throttle open): 4.70 kΩ - in spec​
Voltage readings (colors still apply):
  • Blue (positive) to yellow (negative) (throttle closed): 4.28 V - out of spec
  • Blue (positive) to yellow (negative) (throttle open): 1.12 V - out of spec
% Throttle range in diagnostic mode:
  • 17-96 with idle screw turned in, 15-96 with idle screw out. No gaps in numbers and each number can be seen when rolling the throttle - in spec
I’m not sure what these results mean. Most of the values are in spec according to the manual except for the voltage readings. I would have assumed that a bad tps would give out of spec resistance readings, not voltage readings. Could it be my ECU?

It’s like $150 to replace just the tps, so I would like somewhat of a confirmation that it is the actual problem before shelling out the money for a new one. Any ideas would be greatly appreciated.
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