Modern Vespa

Hello everyone, here i am again. I have a very weird problem with the mp3. Maybe someone recognizes this or has had it. I noticed it all of a sudden but I think the problem came gradually.

When I use the rear brake, the engine cuts out. This only happens when I have almost come to a stop. If I'm just driving and I use the brake it doesn't cut out. It happens even when I use the foot brake. I can only squeeze the front brake as hard as I want but then it doesn't cut out. Sometimes when I use the rear brake to come to a stop, you hear it want to stall and when I squeeze it, it crashes. I've been through a lot of crazy issues with it but this one is really a mystery. I already checked if that pin of the asr\abs is not good but everything looks good. now it's still quite dry it doesn't give much problems but in wet or cold weather I want to come to a stop with the rear brake and not with the front.

Initial guess is that the "clutch" is not disengaging when coming to a stop. Granted, this is a CVT but it still has to engage and disengage the engine to the driven wheel.

Specifically, check the metal bush on the crankshaft and make sure the cone slides freely and smoothly without catching or hanging.

With every belt service, I put a very light coat of high speed bearing grease on the outside fo the metal bush and fill in the 2 grooves on the inside of same bush to keep things lubed.

Also lightly grease the needle bearings inside the rear clutch assembly. Just a fingertip of high temp bearing grease is enough. Less is more is the key here.

I'm pretty sure the problem isn't there because the front brake can still be used. I understand what you mean and when you let go of the gas, you also feel that the clutch grabs the belt at the end. But this is really weird, even when I stop braking, the engine revs up again. It's like there's some kind of off button on the rear brake. I tested it recently and if I brake hard above 3k rpm nothing happens but below that it revs lower and then cuts out as long as I squeeze the brake, if I release it just before it cuts out it revs up again and it stays on. I'll take it apart a bit over the weekend to see where it's coming from. I also checked the killswitch and the air filter. But it was al just fine.

Check and adjust your throttle cables if you haven't done so already. They might be binding.

One more thing, also recalibrate the ASR per the instructions in the owner's manual if you have not done so already.

The ASR is very intrusive on these bikes. Hopefully that is all it needs.

Both cables work well, the back and forth works well and is not loose either.

I didn't know you can calibrate the asr. but in the manual I can't find anything about it, but I also couldn't find a workshop manual for the 300 hpe.
At first I thought the throttle had to be calibrated, but I saw that this can only be done with the obd.

But none of the brakes are connected to the engine, so I really wonder how that interacts. Today I also had to brake hard for a car and immediately fell out again. No malfunction visible on the dashboard. Crazy mp3 stuff. If i am not riding then there is always something else what happend.

1. With ASR "ON" ride a short distance above 3 mph until ABS and ASR lights go off
2. Allow engine to idle for 5 seconds
3. Pull Hand brake simultaneously will pressing the "ASR" button for 3 seconds. ASR light will now flash slowly
4. Accelerate to a constant speed of 18-15 mph for at least 8 seconds (ASR will flash fast)
5. After procedure switch ASR "off" wait 60 seconds; then turn on.

Thanks for the info, I didn't know that. I'm going to try this over the weekend.
Also I found someone who has the software from piaggio. So I may soon be able to read and update problems myself.

You know "someone" that has the PADS? That's odd, because it is sold only to official Piaggio dealers, and besides the high hardware purchase costs it requires a supplementary annual subscription with Piaggio.

In other words, just having the Piaggio diagnostic hardware is useless unless it has a active subscription.

Unfortunately your trick didn't work, I couldn't manage to perform the steps properly. But after looking closely I saw that the rear brake system also goes over the rolllock, so I think that something is wrong between them, also because it is only the rear brake. The front brake is drained from the reservoir and the rear brake continues past the rolllock.

No, it is not a pads system but a standard OBD system that can read. unfortunately the system cannot send a signal back so updating is not possible. I'm going to see what the system can do this weekend and what I can read.

Happy New Year to all. Unfortunately, the problem with the brake is still not solved and if I brake with the front or rear, the mp3 cuts out. I also saw yesterday that the seat sensor is not working. The red light is no longer on and it no longer sees that I am sitting on it. If I disconnect the cable from the sensor, the red light is on and it does nothing else. The engine also sometimes cuts out when I stand still. The mp3 starts fine and drives well. Could it be that the sensor is broken and stays on? If I put pressure on the saddle nothing changes. Does anyone have an idea what it could be? My thanks are great.

Maybe a the sensor problem is your problem, maybe when you are braking hard it moves you around on the seat and the sensor fails

That's what I thought at first, but I disconnected the sensor from the rear wheel and drove for a bit, but I didn't notice it at all. I haven't tried the sensors of the front wheels because the problem was only with the rear brake at first. But only the sensors can see when you come to a stop, so it seemed to me to be there too.

Does anyone know if there is a sensor for the kickstand, if I remove the mp3 from the kickstand, it sometimes falls out.The failure only happens at low speed. Can it also be the abs that is not working properly? I didn't see any lights come on.

So the problems are when I brake, the engine cuts out(Not always) Seat sensor does not see me on the bike, the red light does not come on when I go off. And the engine sometimes turns off when I stand still or go off the stand .

Sounds like bad seat sensor or wiring issue to sensor

It must be that the saddle sensor is broken because if I disconnect the cable, the red light of the rollock will light up. But even then the engine will cut out when braking, so it is not the sensor that causes the problem. I have looked at all wheel sensors, but there is little to see.

Today I did measure the battery and I saw that it was 13.8 volts with the engine off and 18 volts with the engine on. Now I'm starting to think that the voltage regulator is not good, but does this cause such problems?

Yes, 18V is way too much and is cooking your battery.

The regulator should keep voltage to just under 15Volt max.

Excessive voltage will damage the electronics given enough time.

I also thought it was definitely not good that the voltage is so high. Now I happened to be at the motorcycle shop and I asked why the voltage is so high, the mechanic was kind enough to measure their hpe, and also exactly the same. Between 15 and 18 volts. Now I don't get it at all. The mechanic says that my saddle sensor is broken and the system does not know whether I am sitting on it and therefore fails. I will have to remove the seat cover then check the sensor. Only such a sensor is not sold separately, so does anyone know if I can also use a sensor from another mp3?

Replace the voltage regulator first and foremost before it causes some real damage.

Don't be surprised if your battery has already suffered a fatal blow.

There's a chance the high voltage is causing a false positive and thus playing tricks with the bike's electronics.

I'm going to measure the volt regulator to see if that's it, thought there was a trick for that. I can imagine that the system gets upset by too high a voltage, but it is strange that the same mp3 also gives those voltages. My battery also does not seem to have decreased and starts up well every time. If the measurement shows that the voltage regulator is broken, I will replace it immediately.

Easiest way is to measure (in Ohms) the 3 fields at the plug going from the regulator to the stator.

I was just looking but couldn't find that damn voltage regulator, I thought it's on the front next to the horn, but that's not the case.I think these voltages are a problem!


This was with the engine off

This was stationary

I think this is the end of my mp3

Yep, definitely regulator or stator problem but most likely regulator.

With those voltages, consider your battery toast (literally). Anything over 18Volt is usually lethal especially to electronic components that like to see 12-14Volt.

On the 500, the regulator is mounted on the poop deck between the rear lights.

What is very strange is that the battery does not get hot, and the cables do not feel really warm. I am sure that this is not good for the system, which is why it fails with the brakes and all other strange things. The hpe 300 comes with this one not at the rear light because I must have seen this when replacing the cylinder. So I have to find out where it is on this one