Modern Vespa

The book says 80 w 90 Synthetic API GL4. The only synth. oil I could find was GL5. The only GL4 I could find was not synthetic, it only says Hypoid.

What are you guys using? I have a 250, 2007.

Thanks

I use Shell Rotella T6. I've found it at WalMart and Pep Boys.

Motul 75w90. All you need for any model.

Gearbox oil bro.

T6 would be Synthetic? Is the Motul a synthetic oil?

Ooops! my misunderstanding

sticky addressed it.

I use belray

Yes Motul is synth.

I use Motul 75w140 Racing Syn.

I will try to find some Motul here. We have the Belray non synthetic but I do not remember if it is GL4. I was reading an article on the forum and they do not recommend using GL5 only, too much additive and it is corrosive. Motul is GL4 / GL5 oil and synth.

Here is the info.
Gear Oil for Shifty Vespas

So GL4 synthetic would be the best, but apparently hard to find.

Both GL4, been using them for years......Most modern vespa's use 80w90 gear oil as stated in service books and manual etc etc, but i no
people use 75w90 with no issues also.

A lot of places near me use the Silkolene stuff.

http://www.opieoils.co.uk/c-795-scooter-gear-oil.aspx

Thicker is not better and can cause early failure of the bearings or wear of the gears.

I called Piaggio about this before using and they really didn't have any issues with it. It's an "Oil Bath Lubrication" of the Gears they explained to me.
I have 6 1L Bottles left from my Genuine Buddy Days, and will use it until gone then switch to 75W90 Spec...

Keith,
Marietta, GA

Mobil 1 gear oil.
I've decided to change it every-other rear wheel change.

If I understand Gear Oil for Shifty Vespas correctly, that would mean:

For those easily found on store shelves -
- Royal Purple or Lucas 75w-90 would be an ok choice (meets GL-4 or GL-5)
- Discouraged - Mobil 1, Valvoline Synpower, or Castrol Syntec 75w-90 (all are GL-5 only)

For the harder to find ones -

- Red Line MT-85 75w-85 would be best (GL-4 only)
- Motul is GL-4 or GL-5.

It is strange to me that Amsoil is GL-5 only, since it is so highly recommended on this site.

RED LINE'S MTL OILS ARE GL4 SPEC. This means they are formulated for hypoid gears under severe service without using EP ( extreme pressure additives). EP additives are corrosive to all non-ferrus metals(aluminum, bronze, and brass) . GL5 spec lubes contain 30-50% more EP additives then GL4. The Piaggio MP3 rear diff does not need a GL5 spec oil. GL4 would be a better choice.

The original API GL-5 spec lubes did indeed have sulfur compounds that attacked "yellow metal": but only at temps above 250 degrees. That was cleared up long ago, and virtually all GL-5 today also includes the MT-1 designation, including RedLine's.

"Yellow metal" is any alloy containing copper; in the automotive/motorcycle world, that means brass or bronze. There is no brass or bronze in the MP3 rear end.

This belief that GL-4 is better comes from manual transmissions (not differentials) using brass blocking rings (synchronizers or "synchros") to match rotational speeds between gears to make smooth shifts. When GL-5 first came out, it did indeed raise havoc with RACE TEAM transmissions (frankly, the only use* that will get operating temps to 250 degrees or more). Porsche had some notable failures...

Nowadays, Porsche specs GL-5 for all of its manual transmissions. That should tell you there has been a change in formulation.

OTOH, GL-4 has plenty of load capacity for what is a very unstressed rear end. The very nature of a scooter with a belt and CVT and centrifugal clutch means that shock loads are not a concern.

So, in the end, it just doesn't matter. Whatever you believe and pick, won't amount to a hill of beans...

Cheers!

John

*Unless, of course, you park a Terex© in your garage. Then, I apologize. But even then, you should still be using GL-5. Heck, the Army uses it in the M1-A1.

To say it somewhat differently, many currently available motorcycle gear oils are rated GL4/GL5. That means they use a formulation that meets the GL4, as well as the GL5 spec. Use one of those (many available) and you are certainly fine.

It is splitting hairs, but GL4 is still a better choice. Thats why piaggio is GL4 spec. The sulfur was replaced by " Less Corrosive " EP additives.Those newer additives do wear non-ferrus metals faster in a GL5 spec, then a GL4. Metal alloy compounds were also changed in newer components in most gearboxes.
Aluminium is still exposed in all Piaggio Scooters. GL5 does not superceed GL4 nor can a gear lube be both.

It's like alcohol running though a liver.Too much of a good thing n it all gets messed up!So what ever ones decision is ,hope it works out.

Like I said, it doesn't matter...

But your information is incorrect. It is no longer possible to test an oil to be compliant with GL-4, the testing equipment no longer exists. The only true GL-4 spec stuff available is stuff whose formula has not changed since before API Publication 1560 was published (July 1995), and there is no way to test that it still meets the spec.

GL-4/GL-5 oil is GL-5 oil, plain and simple. GL-5 meets or exceeds all GL-4 specs, and the only reason it is marketed with GL-4 in the title is the urban fiction that is still passed around.

The sulfur compounds only ever attacked copper alloys, not non-ferrous metals. They were chosen to replace phosphorous compounds that served the same purpose, which was to make a sacrificial, sticky layer on the blocking rings. The blocking rings are really cone clutches, and with the improvement of oil the brass was literally too slippery to function. The original sulfur compounds were too aggressive in creating that layer; subsequent refinements ended up with packages that create just enough of the sacrificial layer.

So, you can either pick an oil thats formula hasn't changed for over 20 years, or you can pick a modern oil and benefit from two decades of development. It still doesn't matter. There is no brass or bronze in your rear end.

BTW, aluminum is still exposed in virtually every motorcycle and aircraft engine in the world. Sulfur is a naturally occurring element in petroleum, and I have never seen any evidence of sulfur corrosion in even 100 year-old aluminum crankcases. (Penzoil - e.g. Pennsylvania crude oil - got it's reputation because the petroleum in the Pennsylvania region had appreciably less sulfur that virtually all other crudes. Low-sulfur crudes are referred to as "sweet", not because of less corrosive effects, but because they don't stink so much.)

But hey, pick what you like...

BTW, my service manual specs GL-3. That is an inactive spec...

John

Decided on Motul Gear300 synthetic 75W-90 - it was recommended on scooterwest website (for automatic).