Modern Vespa

Just had a customers scooter in with a not starting problem, compression was low, On stripping it down to see what the problem was i found melted piston.
It held the rings into the piston as you can see from the pics. oil was good fan was working as it should and the coolant was good and at the correct level. he told me the only thing he had done differently was to use E10 petrol as his local filling station had stopped selling E5, and he would have to ride 10 miles to get some. he was advised by the garage owner E10 would be fine, well as you can see from the pics, Its not.

What scooter including what year?

GTS 250 2011. i transplanted the engine into a scomadi frame 4 years ago.

I know an HPE is fine with E10 (according to the manual) but I don't make such an assumption about such an old engine design.

Most of the information on E10 suitable engines refers to the rubber seals etc, but the materials that the piston rings and barrel are from are the same, This is heat that has caused the problem, hence checking all the fluids etc, there is no wear in the crank, I cant find anything else that would have caused this kind of damage. i have seen the same thing happen with 2 strokes, but its the first time ive seen it on a 4t.
I run a 1965 BSA 650 star, i use an additive With E5 lead replacement because on the older engines valves etc take a battering from E5 without additive. The valves on the gts although no visible damage is present they are light coloured indicating it is running lean and therefore hot. I always recommend a remap when i do these conversions, Not for more power, but to make them run richer, the Euro regulation make all motor vehicles coming into the country meet the emissions standards, which are not good for engines.

Just to say that if you're U.K. based, look at Esso's premium fuel.

In a lot of the U.K., it has to be labelled as E5 but is actually completely ethanol fee.

https://www.esso.co.uk/en-gb/fuels

Thats very interesting , and i shall be buying mine from esso in future. thanks for the link.

That looks more like oil starvation than using the wrong gas.

what's the face of the piston look like?

highly doubt a few miles of bad gas would do that type of damage.

I once owned a Honda RS 250 which had been run low on oil and it looked exactly like that.

It looks like the piston skirt has been scoring up against the liner and destroyed the ring's integrity.

Has anyone checked the dipstick ?

At least on the West Coast of the US, most GTS 250s have been run on E10 gasoline. I owned a 2008 myself and ran it primarily on E10 for nearly 6 years of ownership. Likewise my 2015 GTS 300. Piston failure was not the result in my case, nor in the case of the overwhelming majority of other Quasar engines run on E10 fuel. I think you will need to look a little further for likely explanations.

my thoughts exactly. admittedly I had to google up to see if there was a difference between UK E10 and Cali E10...

I'm thinking it was run low on oil, or went well past the OCI for quite some time.

ETA: spelling

Piston face shows no sign of pre-ignition which I was always informed was a sign of unsuitable fuel. I think something else is the problem. I also run my 1972 Trimuph 500 on e10 with lead substitute without a problem. The main issue with ethanol is its incompatibility with rubber, plastic and hydrophilic properties.
I hope you get to the bottom of the failure. Please let us know what the final outcome is.

Did the oil look like it had just been poured in?

The cylinder, pistons and rings are totally happy with E10 - or E95 for that matter. It's the other bits that need to be appropriate for the fuel.

I call fake news.

For E10 the standard according to NBN EN 228: 2017 is ethanol max 10%, for E5 it is max 5% ethanol. A minimum is not specified.
So, for both E5 and E10 the fuel offered by a specific brand can be ethanol free.

I am running my BV 300 ie from 2012 with the Quasar engine on E10 without any issue for over 10.000km.

I ran a 2006 GTS 250 for 10 years on E10 in Houston. Sold it to a guy who is still riding it in Houston. The closest ethanol free when I lived in Houston was 70 miles away. Probably still isn't any closer.

When available I prefer to use ethanol free but that only happened on road trips and even then it wasn't common.

I have had a lot of damage caused by E10 on several different bikes and cars. But never an engine itself. It has always been plastic and rubber parts of the fuel system. I had two oem Honda plastic dirt bike tanks destroyed by it, but I had left it in the tanks for months. I also had an aluminum carburetor body destroyed by it, but again it had been in there for over a year. Mostly it has been the rubber and plastic parts in the fuel systems.

2 stroke engines can be damaged by it under certain circumstances. For some reason, synthetic oil doesn't seem to mix with it as well as conventional 2 stroke oil. But that is a 4 stroke engine. I have to agree with Bill Dog, that looks like damage caused by a lubrication failure to me.

If you own a shop, you know that what you're saying is not true. If E10 destroyed motors like you maintain, your shop would be rebuilding top ends all day long. More than likely ran it out of oil, then added some before bringing it in to the shop. I've seen that a lot. They feel like it might be cheaper if you don't think they broke it. OTOH, that is one clean piston, and you can see where the top was starting to break down at the edge, which might imply that the bike was running quite a bit on the lean side. I've never seen a piston come out of a Vespa that clean, especially after four years. Show us the plug.

Around here the octane number (RON) guides the use cases: we have 98E5 and 95E10.

Vespa recommendation here is:
-95E10 for all over 50cc engines with fuel injection
-98E5 for all 50cc engines and larger with carburettor

where is everybody seeing the top of the piston at? I only see the view from the side where the ring pack is and the barrel.

also, looking at the motor, why does it appear as though the coolant is straight up mud? is it just the lighting? if not, that was wayyy overdue.

The top of the piston can be seen in the bottom picture, at BDC. Notice the huge gouge in the cylinder wall. The studs are definitely caked in something. It could have been a lubrication failure, severe overheating, or a mechanical failure in the engine, but it is not related to ethanol.

no, look closely, there's no dish for it to be a piston, that's the workbench top.

Your right. It was 2:43 in the morning and I was half asleep.

Agreed, the coolant looks really grungy. I'm guessing it is more of a sludge mixture - Coolant and oil cooked together. That engine needs a total tear down.

That's settled then. E10 got into the coolant.

Is this an oil thread yet?

It's a lack of oil thread.

Or lack of coolant thread - that top end got fried

If you put the monitor on the edge of the desk, then get under the desk and look up, you can see it in the first photo.
I was mistaken, that is definitely not the top of the piston. And it looks like someone scooped water out of a puddle when they ran low on coolant.

Oh, a puddle....
I had a totally different hypothesis....

Where is the popcorn?

We ran out of oil to cook it with.

I'm still waiting to see the piston crown. and the combustion chamber. and while that's open let's see the cam and rockers.

I have a hard time believing *anything* was tip top just looking at the nastiness of that coolant. I can only imagine the rest of the motor was cared for with the same regard.

the funniest thing is that when people bork up a motor real good they always come in with fresh oil or recently changed or grossly overfilled from topping up after realizing something has gone awry. all done in hopes of saving something beyond repair or hoping the save some face.

Perhaps someone has never seen this particular obfuscation?

Had a customer years ago with a Runner 180 who run the 2T oil tank dry. Came in with the tank topped up, shouting, raising hell and demanding for an engine rebuild under warranty. Oil line was full of air. Showed him the line, took a photo and emailed it to Piaggio's tech dpt. along with his VIN…

In 1972 my wife ran my Suzuki 185 enduro (2t) dry of injection oil. Piston looked just like that. Piston actually welded itself to the cylinder and pulled out a chunk. That's an operator failure. Suck it up and give the mechanic his money.

Just because "there was oil in it" doesn't mean the oil pump was doing its thing.

X9's used to be notorious for chewing up the plastic oil pump gear if gas (petrol) got into the oil - a common occurrence for those who just used to ride a couple of miles to the station and back, so the engine didn't heat up completely.