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Mutley53

2010 Throttle Position w/ GYTR Tuner

16 posts in this topic

I have a 2010 YZ450F and I recently purchased the GYTR tuner. While I was playing with it I noticed my throttle position only goes up to 80 either while running or with the engine off. The bike seems to run fine, but I wonder if I am missing some performance because of this. Should I replace the TPS or is there any way to recalibrate it? Like I said, the bike seems to run fine (I can run with a '10 KX450, but the rider may be a factor). Is this common, or is my bike messed up? Is there any thing else that could be messed up? With the throttle fully closed, it reads zero (0), according to the manual it should be 15-19

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If we can assume that the readout on the GYT-R Tuner is the same as that of the Diagnostic Tool, then the TPS clearly needs to be adjusted. But I don't know if the two tools agree with each other or not.

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That is really interesting, on my PCV it will of course read 100% but since the tuner ties directly into the ECU maybe that 100% is really only 80% as well?

Going to check my bike right now.

Are you sure that your throttle is working correctly? Could be a crack in the tube causing it to catch on the edge of the bar or something at 80%?

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I guess I assumed the GYTR would have the same readout as the diagnostic tool. That could be wrong. Can someone with the GYTR Tuner give me their readouts for throttle position? I would think it would be a good assumption to think that the throttle position should read from 0-100, but the readout is in deg, so 80 deg may be the same as 100%. Any ideas?

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Just checked my bike, and mine reads 81 at WOT.

However the gauge is in degree's not percent, so it is possible that 81 degree's open is actually 100% throttle?

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If the tuner readout is in degrees, I would guess it's going to be the same as the diagnostic tool.

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lol beat me to it, looks like we have this figured out, 81 degrees has to be 100% throttle.

I guess the only way to be 100% positive would be to remove the throttle body with it still connected to the harness and see if you can turn the throttle cam all the way without cables and check the readout.

However I really doubt that yamaha would limit throttle openings on an MX class bike. They have done it I believe before on the TTR's (small ones) and some of the bigger ones if I remember correctly.

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Thanks for the replies. If another is reading 80-81 when fully open then I think my bike is normal. I was expecting 0-100, not 0-80. I have experience with a powercommander which lets you calibrate it and is based on throttle percent, not degrees. I feel much better now. I only have 42 hrs on my bike and it seems to run the same as it always has, but if it was messed up I wouldn't have been too opposed to trying a new TPS.

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I had just read the 2010 Yamaha YZ450f dealer training new model updates, the reference that someone said about 80 degrees or what not is true. Its not an actual percentage but its measured in whatevers. And sometimes yamaha will "hide" this info in in dealer tech updates and its fi books and training materials. Can be very annoying.

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There are two things to be considered:

One is that the indicated and actual degrees may be different.

The other is that the throttle plate does not sit at 90 degrees to the throttle body bore when closed. If the closed angle is around 10 degrees, and it probably is, and that point coincides with 0 degrees of TPS angle, then 80 degrees of rotation would align the plate with the bore axis.

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Interesting note. I decided to adjust the TPS to get the same values as referenced in the manual. Adjusted the TPS so that at fully closed throttle the readout was 15, and full throttle was 95. This was done with the engine off. Cool, I thought. Figured I would try it and if it ran worse I would just reset it to zero when closed. Fired it up and made a few laps. Seemed to run fine, no noticeable difference. Plugged the tuner in to check it again and it reads zero at closed throttle and 80 at full. Seems the ECU learns the fully closed and fully open points and goes from there. Since the bike runs great I may leave it, or I may reset it based on the resistance readings in the manual this time.

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i removed my tps then later read in the manual to never remove it. i put it back in at "about" the same position, but it says i need a harness to go along with my gytr tuner to calibrate it. where can i get this harness?

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you can also do it using a dc multi meter. if you give a 5v input into your tps on the yellow line and take the reading coming off the blue line you can set it that way as well, but i am unsure the voltage for the ouput. this is how they set them on the at the factory in most cases. i assume it is around .6-.7 volts, but dont know for sure.

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