Modern Vespa

Greetings,

Its been I think over a decade since I posted on here, but before I ask my question, let me share a little story that I think folks here could really appreciate.

I bought my 2008 mp3 500 in 2008 in central california and owned it through a move to Houston, TX. After witnessing how people drive here and my lack of familiarity with the city (plus having 2 toddlers), I decided to sell the mp3 because I didn't feel safe enough to ride it anymore. I ended up selling it to an italian man who traveled back to Italy for work on the regular and worked on vespa's his whole life, so I felt really good about where it was being rehomed to..


Fast forward to 2023, that itch to own a bike never went away. kids are older now and covid means I dont have to drive downtown as often anymore.. I was well on my way to buying a new ducati Scrambler 800, but just out of nothing more than sheer curiosity, I checked facebook marketplace just on the offchance that there was an mp3 for sale. ( I doubted it, because other than mine, I've never seen another one driving around here.) Yet wouldn't you know it? 4 days prior to my search someone put up an mp3 500 for sale and it looked EXACTLY like mine. suffice it to say, as long as the colors match, they all pretty much look alike.

I reached out to the man selling it, he was a Greek man who retired and happen to buy the bike from in Italian man who decided to sell it, but gave him a ton of extra parts that he would buy in Italy on his travels...

Now, I couldn't find anything at the moment with the VIN or persons name to confirm, but his asking price was right and I never sold the MP3 because I didn't love it. I ended up buying it and as fate would have it, my wife found an old document with the vin and it was an exact match! I just became the proud owner of the same mp3 twice! (Small .. World!)

Now, the downside is, this gentlemen didn't hardly ride the scoot at all. In fact, the gas sitting in it is the same tank of gas he bought it with 2+ years prior. (which means it wasn't maintained at all).

Taking a risk, I rode it over 45 miles home, but it died at every stoplight with an extremely rough idle, check engine light came on a couple times when the engine felt loaded down, but stoppped, let it set a minute, and the light went away. Now that its home, I'm trying to figure out everything I need to do. I have absolutely no idea how to drain the fuel tank (nor do I think my HOA would allow me to do so where I live). I topped the tank off with 92 octane and put an octane booster in the tank in the event I just need to burn through this tank of gasoline. I read several other posts on this forum of things to check:

Spark plugs: They're on order and should be here wednesday, but I did take a picture of the connecting wires inside the boot and they looked clean. It appears that the owner I sold it to, based on parts I have, changed the plugs every time he changed the oil, because the amount of used plug he had in parts doesn't add up when you consider the mileage difference on the bike since I owned it and now. The older plugs look properly used, not fouled, but I figured to start fresh would be best.

Air filter: I took it out and it really appears very clean considering how long its been setting. I've provided pictures of it and the filter box in this post. Also, what sort of oil should I be using to recharge this filter? What is most readily available near me is K&N oil but if there is a better one I'll order it.

As the feels like temperature right now is 117F (about 42C), and I'm no longer young and immune to the elements, I stopped for the day... BUT:

Oil: I read the religious debates of what kind of oil to use, and ended up buying a few quarts of Castrol Edge 5w40 full synthetic as it was readily available and plenty of folks appear to use it stateside. I plan to replace the oil once I have the new plugs

Throttle body cleaner: I the pros and cons about using cleaner versus removing the TB alltogether, honestly either are a bit daunting to me just because I'm not completely clear how to access the TB in order to use the spray cleaner (I bought the MAF throttle body cleaner, as I read it should be the best on the sensors the bike uses), and this seems to be something that isn't well covered on youtube (at least I havent found it yet). I understand that the airbox and air intake needs to come off, but where/how to spray it, and doing it in such a way that I can increase the throttle seems a bit mystifying without a second person.


I really want to get this beast back into good running order.. I've posted a video hoping it might stir some audiovisual concurrence with others that have experienced problems and maybe can suggest other things to try? Unfortunately, I didn't realize until today that the only Piaggio dealership in Houston closed during covid, and the closest one is in Austin (about 3 hours away). I've yet to find anyone who has experience with mp3's to take it to, so I think I'm on my own to get it at least up to a 3 hour road trip to austin where I can have it truly gone over. (Unless anyone knows of a person/facility in houston, thats still operating in 2023, I can take it to!! )

I'm excited to be rejoining this community. I see some names on here still posting from back when, and it doesn't surprise me. This was always a great and helpful community.

I appreciate any advice or feedback you can provide on the issues im having.



Video link 1:
https://photos.app.goo.gl/SH2ULatzcyL2QoeB8

Video link 2:
https://photos.app.goo.gl/KsuvQQ6vUPBWMoxKA


Mike

I can see why you want to restore the bike with a wonderful story and nostalgia linked to it. At this point its not about how much the bike is worth so much as the memories and simple fun that goes along with such a project. Its worth it .

I wont pretend to be a mechanic, however, based on your description it sounds allot like other stories where the culprit of the stalling bike was a bad fuel pump or fuel filter.

Likely your going to have to take some plastic panels off to really inspect the bike. With that assumption you should use the opportunity of having the plastic off to do as many consumable (filters, oil, etc) replacements as possible.

Mitch's Scooter Stuff. channel has allot of content for the older Mp3 series.
https://www.youtube.com/playlist?list=PLt2M_Fbbcf03hRIiBRxeDrrfTGbng9y3D

I doubt it - these are classic symptoms of a gummed up throttle body idle bypass passage, which can easily happen when a bike is left unused for a while and then run with old fuel.
https://cheekythoma3.wixsite.com/itsme/idle

Jimc'

I did read this article before posting, but I was confused if I could simply spray directly into the throttle body when the butterfly is open? I'd read other people say that caused them some major issues. This is what I ended up buying with the final outcome Being doing exactly that. Most of what I'm used to working on are cars from the 1960s that didn't know what a sensor was...

https://www.autozone.com/miscellaneous-cleaners-and-degreasers/electrical-parts-cleaner/p/crc-mass-air-flow-sensor-cleaner-11oz/36011_0_0?spps.s=6192&cmpid=LIA:US:EN:AD:NL:1000000:PER:19488533498&&CATARGETID=120054150001289410&CADevice=m&gclid=CjwKCAjw29ymBhAKEiwAHJbJ8phfVBQ2zLD5SM-ZTGHB1UlnTnNzDYJVj0bbcPl4iBWuVSKVxw3cqxoC5KsQAvD_BwE&gclsrc=aw.ds

Thanks for the additional info about the fuel pump and filter. I'll start scouting those parts if this ends up not fixing it.

You need to spray into the bypass passage. You have to take off the inlet tube (from the air filter), and use a mirror (or very good judgement) to spray directly into that idle bypass, giving it some blips of throttle to keep it running and sucking the cleaning fluid through.

You could take the throttle body right off and spray through the passage. This might be the best way. Do this several times, waiting a few minutes between each attempt to help the cleaner dissolve any gunk.

Jim, just to make sure I'm understanding completely, the bypass you're referring to is the stepper motor inlet in the article?

Yes. Not my article though. It was written by cheekythomas https://modernvespa.com/members/cheekythomas - a friend of long acquaintance via various forums.

If you take off the throttle body, you're best to get cleaner in from both ends.

Thanks Jimc! Are there any gaskets I should get beforehand and
replace if I do remove the entire throttle body?

Here's the Robot video on a GTS throttle body which should give some pointers.

Finally got to a point where I wasn't going to melt to do this. Here's the video. I know channel locks are a bad idea but I had no choice.

Using channel locks holding it at 3k rpm before I started this video. I bumped maf cleaner into that inlet for about 10 minutes. As you can hear after it's still running pretty bad and stalling out. Should I continue until the whole can is discharged?

https://photos.app.goo.gl/j79jFctv8DLsDkRj9

Hi toupeiro
How goes the repair of the Mp3?

If you haven't seen it, there is a similar thread where someone ended up using the whole can of cleaner to eventually get things cleaned out.

2008 500. Start..cutout..Start…cutout… eventually start!

The journey continues.

Completely drained the tank and put fresh 92 octane in the tank.

New plugs.

More cleaning in the idle inlet

Still studders and falls and spits and dies.

Doing other inspections I noticed a 30 amp fuse that got melted pretty bad. I replaced it but the plug itself is pretty bad also. I think this is the coil.. am I right?

I have a date with a piaggio dealer in Austin in October (about a 3 hour drive). I've called 15 shops in Houston and nobody will touch these or call me back.

Also, I haven't tried this because I don't know what it'll destroy, but with 2 plugs going to 1 cylinder like this, how does this thing run with the plug wires reversed? Is it possible they're reversed and I just need to switch them back? I know how it sounds with 8 cylinders, one per plug but not 2:1.

That's on the starter solenoid. When that fuse goes, there's no charge to the battery.

Use dielectric grease when you re-assemble.

Just wanted to provide a quick update for the forum

Oct 7th I dropped the mp3 off in Austin and had it completely gone over:

1. ECU updated to the latest firmware.
2. Steering bearings replaced.
3. Tow hitch removed. <-- Previous person did this, hated it, asked to remove while they had it
4. Oil pressure switch replaced.
5. Tilt lock pressure sensor replaced.
6. Starter relay replaced and tightened down loose starter post. If starter issues return then starter replacement will be needed.
7. Cleaned the fuel injector.
8. All three tires replaced.
9. Battery was recharged and did not need to be replaced. Please note, the battery is old and may need to be replaced in the near future.
10. Evap system was adjusted.
11. Throttle was relearned.
12. Self-learned parameters were reset.

I'm planning on picking up this weekend and looking VERY forward to riding again now that south Texas finally has some nice riding weather!

I did have one question about the notch issue, which I did confirm my bike had. are the newer bearings of a higher hardness than the stock bearings or are they just as susceptible to this issue over time as the stock ones?

its not the bearing themselfs its the races the bearing sit in and the lack of lubication and improper torque when installed.

Well, the MP3 is home and there's good news and bad news

The good news is, it steers like the day I first got it back in 2008. Paired with the new tires its like butter on the road, which is great!

The bad news is, it still has a rough idle periodically and while not as often as it was, it will still stall out. Now, occasionally I will come to a stop and it will idle beautifully at about 1,750-1800RPM. It all seems to be related to the same behavior by the bike at different rpms. if I put it on the stand, and hold the throttle at 3K rpm, I'll here a few light pops from the exhaust and the bike will load up and drop down to about 2K rpm. The check engine light will pop on. if I bump the throttle a bit, it will smooth back out and then I can hold it at 3k again and the check engine light disappears. I notice it occurring most commonly when I've had to back off and get back on the throttle as in stop-and-go traffic, and after about a minute or so of holding the throttle at a cruising speed. As shown above, the throttle body was taken off and cleaned completely by the repair shop and the ECU / mapping update was done on the bike.

So, by process of elimination, what other things could it be? I've read a few different posts on the forum about the o2/lambda (assuming they are the same thing?) sensor potentially causing an issue like this. I took a few pictures of where I THINK that sensor is. One location reveals something that looks like the repair shop replaced, (and I doubt they'd replace one of those without charging me for it. ) The other one looks, to me more like the sensor and by the looks of it, its original equipment.

The other thing I noted in the manual (the previous owner did take good maintenance notes), is it looked like in June of 2022, he put in a full synthetic 10w40 motor oil, which i know is not the right oil for this bike. I have purchased the right oil, and plan to drain and refill the oil next weekend, but I'm assuming that will not cause this problem.

Does this issue that remains sounds like it could be caused by the O2/Lambda sensor? If so, does anyone have a link or an accurate part number I can source? I've looked on eBay and a few other sites, and there seems to be 2 Bosch o2 sensors that keep coming up with the same part numbers, but the plugs appear to be different. I would definitely appreciate guidance and recommendations for next steps from the community!

Many thanks!

Did the ECU ever get the newer firmwares? The older model Mp3s had a firmware bug that the dealer could flash onto the ECU.

MP3 500ie ECU update (Page 2)
MP3 500 Firmware Update
Vespa Diagnostic Scan Tool and Software

Yessir, that was the first thing they did.

The component with the blue arrow is the oil pressure sender.

The sensor on the exhaust pipe is the lambda aka oxygen sensor. It sends a feedback signal to the ECU to increase or decrease the fuel mixture and keep emissions within tolerance to avoid damaging the catalytic converter and other exhaust components.

The lambda sensors usually have a useful lifespan of about 100K kms as long as the correct high quality fuels are used. Only replace with the exact genuine item. Knockoffs are not worth the box they come in.

I found a spare parts sheet for the mp3 500 and got the part number from that. I see this part number from Bosch associated with it as a reference number. I've yet to find a "genuine" one thats Piaggio branded unless its used. Not sure who sourced or made the original parts for Piaggio, but in you're experience you wouldn't get the bosch part?

Bosch part:
https://www.kmotorshop.com/en/article-detail/view/286342/lambda-sensor-f00hl00193-bosch-639806-f00hl00091#reference

MP3 500 2007-2009 spare parts catalog:
https://www.af1racing.com/ProdImages/st3/ETR7000US1.pdf

that 639806 number is what shows up in the Piaggio spare parts catalog. does that indicate its an adequate replacement?

EDIT
When I put ONLY that number into search on eBay and no other words, I found a new in bag genuine part out of Virginia that I just ordered! I'd still be interested in the bosch one, since price-wise they trend along with the OEM part cost. It would be good to know what viable alternatives are.

Well piaggio did not make it so it makes sense the Bosch is the manufacture for piaggio.

That is a cool story about buying back your original mp3. The MP3 world is pretty small in the states for sure. I am going to be restoring Jess's old 500 this winter starting with replacing the throttle cables. Since this requires an almost total removal of the Tupperware I will be checking and replacing other parts as needed before I put it all back on.

Welcome back and sorry I missed your OP on this.

Well...

New OEM lambda sensor installed and the problem remains. ..

So far I've :

Had the throttle body taken off and professionally cleaned at an authorized service center.

ECU firmware and mapping updates

New 02 sensor.

New spark plugs

New air filter

New oil

New oil filter






I'm stuck! I have no idea what else could do this.

While trying different scenarios with the throttle I did get one backfire on acceleration getting on the throttle hard from idle and it stalled immediately. This is the kind of thing id normally associate with timing on a V8, and have no idea what to do with it here. It's only happened once so it could just be a symptom of throttling up during the event happening.

Here are some new videos I recorded with my phone after doing the lamda replacement awith commentary. Id be so thankful to the community to review these given the steps already don't above and let me know if there is anything else I can do??

https://drive.google.com/file/d/1daw3DKrDdaHU8zODZuZmTIvIzgXedwHA/view?usp=drivesdk

https://drive.google.com/file/d/1daNen8rHiWvutFGCp3-7nqhEc8ohhGv9/view?usp=drivesdk

I don't see you've mentioned checking the valve clearances yet (unless I missed it) - that would seem to be the next step, although a long shot if the problem is intermittent.

Thanks Jim!

Its intermittent from the standpoint that I don't know when its going to happen, but consistent in that it happens every time its ridden. In other words, there hasn't been a time yet since re-acquiring the trike that it hasn't had this problem. I'll dig around the forum about the valve clearances. Is this something that is easily DIY or should I seek professional help?

what jim said.

and the fuel filter (part of the pump) could be stuffed as pinheadh78 postulated

From the symptoms you've given, it's probably not worth getting a shop to check the clearances, as the likelihood of that being the fault is pretty slim. Valve clearance problems will usually be continuously consistent rather than intermittent.

If you're up to a bit of wrenching yourself, it's perfectly doable for the DIYer.

I've not tried that yet. Is it possible to just replace the filter on one of these? From looking at the forum the entire pump and filter look pretty married together. And holy crap it looks like I almost have to strip the thing naked to get there lol.


Thanks Jim! I'm afraid I wouldn't know what I was doing to correct the issue even if I found it to be a problem. I can do very very basic things on my own. Belts, fluids, plugs, wires, carbs, pads, shoes... Things that bolt on. Getting into the guts of things has not ever been my forte.

I actually forgot about the filter idea so thank you for reminding me about it. In line with the symptoms I can't think of anything else to try. I've dealt with dirty filters on cars and these symptoms aren't something I remember which is why I might have overlooked it at first for it being something else. (That said, I was dealing with much bigger pumps and more pistons lol).

I've not found a good teardown video or post on getting to one of these yet. Anyone have any links handy?