TPS Delete & Check Light

[BetaNow]

On my 250Rr RE once I installed the TPS block off plug and unplugged the TPS when i started the bike the check light was illuminated on the dash. To turn that off, instead of cutting the pink wire, I simply unplugged the 4 wire mini connector running into the dash/speedo unit. This turned off the Check light and Icon and left the mileage portion visible again without having to cut any wires. As long as you are not using blinkers this fix will work. Roost On.

[Hurky]

Just out of curiosity , why did you delete the TPS ?

I tried my Lectron on the Beta for a few weeks and as that carb do not have a TPS I used the bike without it (and the yellow warning light permanently on of course), as that was a completely different carb I can not tell if the TPS itself made some difference.

I also tried the Keihin with the TPS unplugged but only for a very short period of time and I was not sure if it made a difference, maybe I need to try it again, what is the supposed advantage ?

Regards.

[Dr Z]

Only reason for a TPS on a carbed 2 stroke is for oil injection. If you premix, you can remove the TPS and oil pump. I installed a smart carb 2 without TPS, removed my oil pump and run 50:1 Amsoil premix. Bike runs flawless with temp and altitude changes.
Oil injection works great and probably reduces pollution a bit, but if it fails without you knowing, bye bye engine.

[Hurky]

I have the racing version with premix, but I thought the TPS would still be used in a 3D ignition map. Not sure why the TPS is in place in the Racing versions if it isn't used for anything, maybe because they do not want to have loose connectors and they can use the same carbs...

[wwguy]

As mentioned above, the only function of the TPS on Beta two-strokes is to support operation of the oil injection system by providing feedback of the carb slide position to the ECU. I've verified this previously by inquiring with the Technical Services Supervisor at Beta USA. TPS isn't used for CDI feedback, which is why Beta offers instructions for removing the TPS, and a plug for the resulting hole in the carb, for those who opt to remove it. (Apparently throttle pull resistance is a bit lower without the TPS in place.)

Regarding why the TPS comes pre-installed on the Race Edition bikes: I haven't inquired about this with Beta USA, but I do know enough about Beta's OI system to make a few educated guesses.

The OI controller is built into the bike's ECU, which is the same for standard and RE model bikes. On all 2T models the ECU is programmed to illuminate the dash warning light for OI system failure if it detects the TPS values are out of the expected min/max range for 0-100% throttle position. There's no plug-in resistor to bypass or fool the ECU for TPS removal like there is for oil pump removal. Additionally, during installation into the carb the TPS must be carefully "calibrated" by rotating the TPS to the position where it provides the expected min/max values relative to carb slide position. Failure to do this correctly will skew the variable oil pump rate map towards pumping either too much or not enough oil across the entire RPM range. This is critical as Beta's OI system is open loop with no ability to monitor actual oil flow, so any errors in pumping rate would go undetected.

To summarize, Beta can offer the RE bikes as "OI ready" by preinstalling and calibrating the TPS, and by installing the OI pump bypass resistor into the oil pump electrical connector already built into the bike's wiring harness. This makes for a simple and straightforward process for an RE bike owner to install oil injection after purchase if desired. From the factory assembly perspective it's also probably less complicated, and perhaps even less expensive, to minimize iterations of wiring harnesses, carburetors, ECUs, and speedometers etc. by going with a single system that's interchangeable with different bike configurations.

Why in the world anyone would add OI to a perfectly good premix race bike is another story...

[typeone]

a blast from the past!

hey, @wwguy, do you still have a line of contact with that Tech Supervisor? a few of us are confused by this statement from Keith Obermeyer at Beta when i submitted this question, twice...

Hello - I have a '22 Beta 200RR Race Edition that I have removed the TPS sensor from using the Beta TPS removal plug. I have heard that removing the TPS disables the ability to switch the ignition maps but did not see this in the Beta parts information. Can you confirm what has happened to my map switch now that the TPS has been removed? Are they related in any way?

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Clinton,

I was told by Italy that with the TPS removed the bike would be in Sun mode all the time. The maps rely on the TPS to adjust the curve based on throttle position and rpm.

Hope this helps.

Thanks,
Keith

[Hurky]

I deleted the TPS on my '19 300 and I did not notice much difference in throttle pull, and I also did not notice the MAP switch not working, but that is something I Never really noticed before , it is very a slight change in this bike. The only way for me to really notice it is on a long strait road at a fixed throttle position and changing the MAP's at the same time. I noticed a little bit of better response and different engine sound ...

I will try to repeat this the next time I ride and will let you know if I no longer notice this with the TPS deleted.

Cheers