Modern Vespa

Hello everyone,

I just purchased and installed the toner wheel to fix the speedo issue and now my speedometer is not working. I followed the directions on youtube and can't find out the problem. Any help is appreciated!

Thank you

I didn't realise they did a modified tone wheel for the LX. Why does the speedo need fixing? They are usually not off by much on these later bikes, and remember, ALL speedos are off for very good reasons that cannot completely be mitigated by a new tone wheel. So even if it works, the speedo by default will still be off at different times, temperatures, and under differing load and speed conditions.

Anyhoo, if the speedo is not working it's because the signal from the sensor is not being picked up. This might be due to a misalignment with the tone wheel and sensor, or the sensor has been damaged during installation.

The new GTS HPE has an issue, when you go full throttle it doesn't let you go the actual speed that your supposed to and it feels as if someone grabs you while driving and holds you back and releases you feeling like a tug and pull situation. This feels like crap tbh.

I am not sure if it would be damaged since I was super careful removing and installing it back.

Yeah, so you have a GTS HPE model, not the LX in your avatar details. Ok. Well, understand the GTS HPE does not have an issue. They go as they are designed to do. It's just that the ecu prevents you from over revving your motor by going over 75mph. That's the tops speed of the HPE. The tone wheel fools the ecu into thinking you are going slower than you actually are so it lets the engine rev higher. It also invalidates your warranty. It's been widely discussed on this site here:
Kubler Speedring GTS 300 HPE

If your speedo is not working I suggest you test the speed sensor for impedance. Full instructions on the values are available in the workshop manual in the Wiki. In addition, is the sensor sitting correctly in it's mount and has not been overtightened? I've seen them split open by over enthusiastic owners with a spanner. Is the end of the sensor in contact with the tone wheel? It must not be in contact and it must be VERY CLEAN. Sometimes contaminates can prevent the sensor working particularly grease with metallic particles in it or grit and dirt directly on the end of the sensor.

Assuming your speedo was working correctly before the fitting of the tone wheel, it has to something you have done. Is the rear wheel mounted correctly? Did you nip up the wiring by accident while refitting the sensor, it's clamping brackets for the wiring, or swing arm. All these things do happen. I've seen the lot. Sorry for all the questions.

...and did you happen to "upgrade" any nearby fasteners with stainless? This messed up my Beo's speedometer, which senses the passing of more ferrous fasteners to calculated speed. Took a while to figure that one out, since stainless contains *some* iron.