Modern Vespa

My MP3 YourBan 300cc 2015 how's a dangerous flat spot in acceleration and also dies mid throttle range until it reaches it full coolant temperature on the coolant gauge.
This is annoying and dangerous. Do these self learn to therefore eliminate the flat spot. What is a way of forcing it to self learn so it over Fuel 's to eliminate the flat spot whilst it's warming up.

The Vespa GTS 300 which probably is using the same ecu does not do any self learning that relates to coolant temp.

Also, have you tried turning off ASR? (Assuming it has it)

What is ASR

Does the O2 sensor change mixture , can it relearn

ASR = Anti Slip Regulation aka traction control

We don't have that on my YourBan.

Could be as simple as spark plugs, vacuum leaks, air/fuel filter, etc, etc, etc

Valve clearances!

It runs perfectly otherwise and doesn't use too much fuel or anything else so to me the last thing you wanna do is start trying to adjust things. I just would've thought there might have been a quick fix. Everything else that's ever gone wrong on my MP3s have been quick fixed via this forum.

Based on my understanding that the ECU is a MIU1 or MIUG3: Yes, that is the whole point of the o2 sensor. It does. It learns continuously. As Jim suggested, when was the valves last checked / adjusted? They are temperature sensitive and can wear a little over time.

Thanks for your update. I have no skill to work on it myself and no Mechanic shop wants to know about it or if they do they have to charge so much which is pointless so I was really hoping there was some learning the ECU work around that we could trigger it into Activating

So it's 9-10 years old - and how many miles has it done?

The workshop manual states valve clearances should be done every 20,000 km on the Yourban 300. Personally on my bikes I leave well alone *unless* there's poor cold running or excess tappet noise.

Poor cold running is a classic sign of valve clearance needing to be checked at minimum, as per more than one Piaggio Tech Memo.

https://manuals.wotmeworry.org.uk/Piaggio/Piaggio%20MP3/Yourban%20300/

50,000 klm

Starts ok , when cold but could be better. Once it's warm it's perfect

I am nervous to undertake any major works

It did have rusted out Welsh freeze plug , no replaced with tapped bolt and sealant

Still looking for a while of tricking the ECU into giving more fuel whilst cold from indicators from the O2 sensor which it must have somewhere

Bike is waaay overdue for valve adjustment

A refusal to do basic maintenance gets all it deserves.

Just get it done. If you can't do it yourself, find someone willing to take it on. It doesn't have to be a dealership - it could be a mate who has the confidence to get stuck in.

Forget the O2 sensor as it doesn't do anything until the engine goes into closed loop mode when the motor reaches full operating temp

I agree 1 million %, also why I quit trying to help folks who want to cut corners. So this question runs through me "why are you here again asking for help then contradicting advice?"

It's got a full service history from a Piaggio-authorised Vespa dealer and has been a one-owner bike since new. Yet, it still has all these problems, which just goes to show that even factory-authorised dealers don't always get it right.

Now that I've rectified the freeze plug corrosion, I'm unsure whether it's worth having someone adjust the valve clearances. To me, it's just a fuel injection issue—though I know valve clearance plays a role, there may be a workaround.

Having owned 25 of these MP3s across five countries, I've found that forums and personal advice often provide the best working solutions.

When it comes to the roller tilt front-end problems, I know exactly how to fix those—I'm confident in my approach. This is the first time I've encountered a freeze plug issue, but now that I've worked through it, I understand it well.

I've also fixed plenty of minor issues using forum advice. Right now, I'm trying to find a way to trick the ECU into delivering more fuel before the engine reaches full temperature, without touching the valve timing unless absolutely necessary. Until then, I'll just live with the flat spot.

WTF!!!

Would love to know more

There's no work-around to valve clearances.

Chasing down cold running on any Piaggio 4T engine once the obvious easy stuff has been done (carb/throttle body clean etc) is on a hiding to nothing until the valve clearances have been checked. The valves are fundamental to the operation, and are always tighter when cold. Sometimes to the point where the engine only just manages to run.

Now, *if* the clearances are OK then you'll have to delve even deeper.

After read this thread and the answer's trying to help, I come to the conclusion that after 25 mp3's who are we to say it could be out of adjustment valves or anything else?

IMO "tricking the ECU" and "workaround" is simply code for putting a bandaid on a infected wound without hunting down the root cause.

Find the problem, work the problem, fix the problem

4 thumbs up and 1 thumbs down. just sayin

Still not sure I want to play valve time. Seems hard to even find the valves

Is there a 1 page tips on how to check valves

Where is air intake can always use aero start

Check your coolant for signs of any oil in it. Could be a slight leak in the head gasket causing a little coolant to get into the cylinder over night. But it's probably valve clearance issue.

Is there a simple one page how to fix and set the valve timing that can be done easily?

My aftermarket MP3 Mechanic says it could be other things like a fuel pump pressure or voltage in the battery which I've tested and used a booster.

Remember it fires instantly it just doesn't keep running and you have to repeat it a few times where you keep your hand on the start button it fires And by still pressing the start button that keeps turning it over it eventually fires a couple more times and then runs which to me is either a fuel pressure issue but not conclusively valve clearance issue

watch one Robot's videos on doing a service of a vespa gts, it'll be the same for the adjustment process as it's the same engine.

Workshop manual probably also has some info on it

I had a simliar issue with my yourban. issue cold starting.

check the pipe that goes from the airfilter to the top of the engine. As mine had split.
See the attached image its only a small pipe that is attached to the clip in the image

Apparently this pipe helps with starting well when I replaced mine the mp3 started fine afterwards.

Worth a look

Have a nice day everyone. This is the crankcase ventilation tube, it goes to the filter. (sorry for my English, I'm writing from a Google translator).

Trying to check mind