Modern Vespa

Well, my 2009 MP3 500 was blowing more oil than I liked into my airbox, even after changing to 50 weight oil and filling only to the low mark. I didn't have any symptoms of catastrophic failure or loss of power, but the bike has 43000 miles so it at least needed new rings.

So I decided to take the engine apart. The worst task was getting the exhaust manifold bolts off. To do so required buying a 13-mm ratcheting flex-head box-end wrench. But that made short work of those little bastages.

Anyway, the bore looked really good (hone marks still prominent and no vertical scratches anywhere). But here's a couple of pictures of the piston. Two cracks on the land between the first and second ring. The first one actually has a little wedge-shaped piece of the land missing. I'm glad I took it apart! It could have destroyed the cylinder at any time!

Anyway, I have a question- I see a "C" marked on top of the piston. The skirt measures in diameter to about the "C" specification in the manual (as far as I can tell). Does this mean that I need to order the -0003 version of the piston from AF1? I know the fit is really critical, so does the -0001 part number correspond to the "A" version, -0002 correspond to the "B" version, etc? Please let me know so I can get the bike back on the road!

BTW- MFR date is 7/08 so it's right in the middle of the bad piston batch.

Why would you run 50W oil in the first place? You want oil to flow for a reason and using heavier weight oil defeats the purpose.

Because it is a High Performance Engine... Motul is Highly Recommended...
See my Signature Line.

To the Original Poster, very sorry to here...
Just reinforces the fact for me, I need to dump my 2016 MP3/500 on a Trade at some point. So far for me, no issues... But I "Baby" mine...

Keith,
Marietta, GA

Not too big a deal- I was planning at least a ring job since it had blow-by and some loss of compression (78% on the leak-down tester). A new piston is not much additional cost, and they improved the piston in 2012- it has a completely different part number. And it looks different- has a visible band of different alloy around the ring lands.

The bad batch of pistons really hurt the reputation of the engine. I just feel lucky that I opened it up now rather than 1000 miles from now; by then the cylinder could have been damaged and it would cost a whole bunch more. As it is, the cylinder bore looks new. With a new piston and rings I'll be fine for a whole bunch of miles.

I had heard that the Piaggio 492cc Master engine routinely goes 200,000 miles on Scarabeos and Evolutions and BV500's. 43,000 is kinda short of that; you should expect 100,000 miles from a well-cared-for modern engine. Some of the folks here on MV whose bikes were built before and after the bad batch of pistons have clocked up impressive totals, so I wouldn't worry a bit about a 2016 engine. I wouldn't baby it too much. I don't plan on babying mine after the surgery is complete.

40 HP out of 500cc is not high-performance. My GSXR big-bore 750 engine (955 cc) was a high-performance engine, but I still used 5w30 in it. Unless you've opened up clearances you should stick to the original weight oil that's called for in the manual. Just tossing in heavier oil isn't going to do anything for protection, and you could be doing the exact opposite of what you think you're doing for protection.

A GSXR engine runs slower and heats less than our three wheels....

Heat is a wound for our machines !!

13,000 RPM is lower than 8000 RPM? Interesting. Liquid-cooled runs cooler than air/oil cooled? Also very interesting. I'd say you're absolutely wrong on both counts. Excessive heat is bad for any engine, but just throwing in heavier oil without doing anything else can do more harm than good.

These big-bore thumpers are known to aspirate oil, in general. It gets worse as the rings/cylinder wears and blow-by gets worse. A heavier oil, at least from the reports here at MV, aspirates less oil. A crankcase less full of oil helps, too. Running at a lower pressure (less throttle) helps too. If you're losing 100cc of oil in 100 miles, changing from 15W40 to 15W50 is a pretty small change that doesn't necessarily hurt the engine and really seems to help with the oil aspiration problem (took mine from 250cc in 20 miles to about 50cc in 100 miles). Maybe lowers the gas mileage by a couple of MPG. Of course, I had a broken piston, but whatever I did either made the piston break or kept it from breaking worse. I like to think the latter, since the spring 2008 engines were known to break piston lands, and mine seems to have happened later than any reported so far.

Maybe when I get the engine back together I'll change back to 15w40 and see how much oil it blows after that. After break-in anyway, since they tend to blow oil for a couple thousand miles when new.

I misspoke, sorry for my English sometimes rough !!

I meant that our engines are often very vocal about their actual abilities and the weight of an MP3 does not help either.
It is the cooling capacity that is involved ...

Here in Paris, some run with 5w60 HP905 and Engine Ice.70 coolant to preserve both the piston and the cylinder

Anything that increases friction that much cannot be good for an engine!

Exactly !
I thought you would add your opinion my friend.
You guys in France provide good information
So far for me, approaching 8K, my Air Box is Clean.

Not necessarily true- a heavier oil doesn't necessarily increase wear. It will be harder to move things around, but the film is stronger.

Take it to the extreme- say you were stuck in the woods with some kerosene and some 140-weight diff fluid and an engine with a dry crankcase. Which would you use in your crankcase? Both are oils, and kerosene has a much lower viscosity and therefore a lot lower loss due to viscosity, but I bet the engine will last a lot longer lubricated with diff fluid.

@ Klaborde-

I wish my airbox were that clean! Maybe it will be after the new piston!

Anyway I count four 5's:

1500cc's, 15/50 oil, under 5000 RPM

13,000 is not lower than 8000 RPM, and air/oil cooled does not run cooler than liquid cooled, so he was incorrect on both points.

Eh bien, il s'est corrigé par la suite. C'est une chose d'anglais en tant que langue seconde.

Agreed. But they're different beasts- GSXR has 4 smaller pistons and requires a lot of oil movement to keep it cool and lubricated. So a thinner oil is better there, and a thicker oil may make it locally overheat from lack of oil flow, leading to all sorts of problems. The MP3 500 is a big water-cooled thumper and it doesn't need as much cooling from the oil, so it's not as critical that it flow so easily. A little cooling on the piston skirt is all. So going higher in viscosity is not as damaging, especially if it's only one click up- 40 to 50 weight hot.

LOL - it was entertaining to see the back and forth on a *slightly* higher viscosity oil.
C'mon guys, remember the days when racers ran straight 50W oil? Squeazel is right - higher viscosity oils have tougher skins. As a result higher viscosity oils also tend to aspirate less oil in a worn engine - anyone here remember STP oil treatment? Sound procedure for an engine blowing oil and it won't hurt a thing.
Now - I WILL disagree on using it to break the engine in. There needs to be mechanical seating of the rings and it will be harder with a higher viz oil.
Best thing to properly seat the rings is to go WOT up a steep hill to build maximum combustion pressure. Do that several times and then ride it normally without babying it.

Amen !
I only have 4 screws holding my Air Box Cover on.
I check it after every Ride...

What I am doing works for me
Now, the minute I see trouble, I will Dump the Bike.
I am optimistic Piaggio will change the Engine and we will see that Bike in the US, then I will do a Trade in.

Keith,
Marietta, GA

BubbaJon! I thought you were gone??!! I've been meaning to ask you- Do I have your old bike? Red 500 with bitubos, a Stebel and LED tail lights? I opened another thread with that title, and if so, you'd been fighting the same darn cracked piston all along with oil in the airbox...

Oh, yeah about piston marking FYI-

Part number B0190180001 is a Cat.A piston, and is marked with an "A" stamped on top. Similar with Cat.B is B0190180002 and Cat.C is B0190180003.

Missed it somehow. What are the mfg dates of the bad piston 500s?
ronkom

You are incorrect and should research this a bit more. It sounds like you are repeating something you've heard somewhere else that sort of made sense, without knowing if it was correct or not. The move to lighter viscosity motor oils has nothing to do with making engines last longer.

There's some data in this post:
Got the engine dropped today. Head off. NOW GOOD NEWS!

But it looks like 3/08 and before is OK, and 10/08 and after is OK, but those dates are probably not exact. Mine was built 7/08, and has 43,000 miles on it, so it lasted a long time. If it was BubbaJon's old machine, then it started blowing excess oil at 25000 miles, which is a testament to BJ's maintenance skills. Typically it seems they start to blow at 10,000 mile or thereabouts.

If you do get the excess oil in the airbox problem, then I would say open it up sooner rather than later- It's not a terrible job to replace the piston but the expense goes way up when the cylinder gets scored or a hole gets blown into the piston and metal gets into the sump. If your bike has less than 3000 miles, well sometimes they blow oil a little until they're broken in. Remember Klaborde's rule of 5's- 1500cc's of 15w50 oil and keep it below 5000 RPM and your airbox will be as clean as his. (I break the 5000 RPM thing a lot, but it's a principle rather than a rule, really).

Yea, 5000 RPM puts me at about 55 / 60 MPH depending on the Highway Grade. I'm OK with that.
Trying to be Humorous, I was cleaning my Air Filter on my Honda Lawnmower this weekend, you just pushed two tabs, and out it comes.
I wish my MP3/500 would do that.

easy enough to do a mod. just be sure to post pics of the honda powered MP3.

That would be interesting...

HEY.....If I wanted a practical scooter, I would have bought a Japanese one.

Only the Italians can blend art and engineering. And there are trade-offs.

But if that happened, you wouldn't have any of these problems in the first place. I really like my MP3, but they are horribly engineered.

Seems like I've joined the ranks of oil in the airbox/piston ring issue on my 2009 MP3 500. Just sucks as I was just starting to use it as part of my daily long distance commute. Just turned 18,900 miles on the bike, so now I have decisions to make...fix, trade or just get rid of it and use my motorcycle(s) to commute everyday.

What's your build date, Spartan1984? Are you in the evil 6 months of bad pistons? If so, best to do the job sooner rather than later. Or not- BubbaJon rode my bike for another 20000 miles after he started getting oil in the airbox. Just use the Klaborde method of 5's (1500 ml of 15w50, and keep the rpm's below 5000 when you can) and the oil problem will be minimized.

I gotta tell you, it's not a terrible job to replace the piston if you do it before it ruins the cylinder. I think I have about 4 hours of (amateur mechanic) work into it, and another 4 hours to go. Total cost so far is only $160, and that includes some extra hoses and new studs and nuts I didn't 100% need.

The hardest job was to remove the header from the cylinder head (just 2 nuts but you can't reach them from any direction; I had to buy a special floppy ratcheting box-end wrench to loosen them).

I think the factory installed the engine with the swing-arm attached. I don't see how anyone could get a torque wrench in to tighten those exhaust nuts unless they did it with the engine outside the frame. I'm going to try and install the engine with the swing arm attached.

I would see this as an opportunity to Trade and get something else.
I am very happy I never got rid of my MP3/250 that works well.

Keith,
Marietta, GA

On the metal placard, it says 05/08...as for the evil months for the pistons, I hadn't been really paying attention to the discussion, so missed out.

Ya, I'm debating what I should do. Luckily, I have two other motorcycles that I can use for my daily commute, with the Aprilia Caponord being the one which would be used extensively.

Yep right in the middle of the evil 6 months. Sorry to hear that. Piaggio should really have owned up to the batch of bad pistons and replaced them for free, but the 500 would have lost money as a product line if they did. Japanese management would have committed Hari Kari over something like this.

Very true...and now that I was just starting to put some serious miles on it, this happens.

New piston is in, leakdown test is at 95%; was 78%. Good to go! We'll see how oily the airbox is when I go for a longer ride this weekend.

Remember, ride it like a new motor for a few hundred miles. Main thing is no long high speed riding and no constant speed, keep changing throttle position.

I'm headed for the Twisties! Riding from Austin to Marble Falls for cupcake, then back. 40-60 MPH and lots of corners!

(I wonder why the forum changes "p.i.e." to "cupcake"? Is there a second meaning to "p.i.e." I don't know?)

Been a while since I posted about this, but seriously thinking about fixing the piston ring issue then selling the bike. Not so much for the ring, but have too many bikes in the garage...lol...would try to combine a sale of the MP3 500 and Aprilia Caponord to get a newer long distance commuter to go along with my fun bike. Right now, its just a thought and things would have to align perfectly to actually pull the sale off.