Modern Vespa

my GTS 300 ie manual says 5W 40 oil should be used. My Vespa Service tech has been using 10W 40 for years w/o incident. Before I do my own oil changes with 5W 40 is using 10W okay?

Sorry to mention this (no I'm not really), but FFS you've been a member here long enough to realise that the Wiki section is for discussion of Wiki articles, NOT TO ASK QUESTIONS!

I'm getting fed up with moving nearly all Wiki posts to GD (or NSM) because members CAN'T READ!


Readme1st ! : Modern Vespa Wiki

You’ll get differing opinions, but I’m of the mind that it’s fine. More so if your local Vespa tech is willing to put his name on the line to “vouch” for the choice you make. After all, if you had *him* do your service, it’d get 10w-40 and you’d be happy as a clam. Don’t overthink it...

20w-50? ...no. But 10w vs 5w - not a huge difference when cold, and exactly the same viscosity once fully warmed up.

I'm too thick to answer this?

You mean you're too viscos!!

As mentioned above, a 10-40 will be fine. My Kawasaki dealer where I bought my new GTS automatically puts 10-40 in the engines at service times. He didn't even know you're suppose to use a 5-40 so I wouldn't worry. At worst it will knock down your fuel economy slightly and reduce your power but it's so slight in a case like this that it's not worth worrying about.

OK I'm not that thick.

At operating temperature the 5w-40 is the same as 10w-40. No difference. Well except at 0 deg C

In truth, when hot there is a very slight difference between the two (5-40 & 10-40) due to the extra additives that make a 10-40 more viscose at it's cold temperature. Of course, when cold there is a difference anyway because the 10 grade is thicker, more viscose due to the extra additives in it over a 5-40. According to it's actual grade, when hot, oil has to be within a certain heat viscosity range. This is not an exact viscosity, but just that, a range, an area where the oil must be at with it's viscosity when at the hot temperature of 100c. This range of viscosity is always measured at 100c. A thinner 5-40 will be nearer to the lower end of the '40' range because it has less viscosity index improvers to expand to maintain the oils viscosity when hot. But it will still be in the '40' range. Remember, it's also thinner when cold because it has fewer index improvers. So that oil is nearly always slightly thinner than a 10-40 when hot. The 10-40 will have lots more viscosity index improvers which as the oil heats up will expand to maintain the oil viscosity at it's cold flow rate and thickness. At 100c the 10-40 oil wil be nearer the top end of the viscosity range, above the 5-40. So this means the oil will be slightly thicker at it's normal operating temperature, but still in the '40' grade range. Remember too, that a thicker oil does not necessarily equate to better oil film strength. It also reduces the oil flow rate which increases heat and engine wear. Although in this case, it's minimal.

A few years ago when I had the 1st service done on my gts300 I did question the 10w-40 oil on service sheet , Was told the right oil would have been used , This was at the same dealer you go to .
Bet they don’t even use fully synthetic

They also don’t have anyway to balance small wheels after tyre change ( yes I did ask this question) Answer was they “ Don’t fit on are machine “
Really for a main Kawasaki/Piaggio dealer you would think they would have the correct information on oil grades and a adapter to fit there tyre machine that’s pretty poor

Yeah, I know. I don't go there for any service work. I'm ex-tech anyway and do all my own work. I took it there for it's first service only, and they hammed it up. Scratched my back wheel loads changing the hub oil, didn't spot a coolant leak and low coolant level, Insufficiently filled the engine oil, but at least with the grade of oil I specified (5-40 fully synthetic). Hammed up the nut and bolt check overtightening my exhaust downpipe stud nuts, bending the collar that holds it all together. Wasn't impressed. When time for it's annual service, out of interest I asked them what the cost was and they quoted me over £400!! They had added on loads of stuff that simply didn't need doing, and in fact it turned out they seemed to have a service schedule on the front desk that was being totally misread. I pointed out their errors and the price came down to £300, which is still far too much. I did the service myself as I was always intending to do and it cost me precisely £36 including all new 'o' rings, filter, oils etc. I did everything as per the book, as I always do even if it's not my own bike that's being serviced.

I think they are into selling bikes but the service side of it is pants, or used to be. It may have changed now because they have new techs onsite.

I heard that one of the techs left as he did not like working on scooters just proper bikes

After the 1st service I have done all work myself on gts300 and quite enjoy doing it , Sometimes it’s a pain like having to remove floor 3 times to finally solve “ That Leak”

The Yamaha dealer is good I have my t-max & Tricity serviced there annually.

Cost for t-max - Annual service + mot + brake fluid change + coolant change was £175 which I thought was pretty good , Tricity was slightly less for same items .

I've decided to use 5W 40 since it's specified and I prefer easier cold oil start ups. I also don't want the additives in the 10W.
Thanks for the input everybody.
Found scooter power 5W40 & OEM Filter.
Regards,Ralph

That's a mighty fine oil...can't go wrong there. Cheers!

I believe the original statement in the tag line was "I'd rather have a free bottle in front of me than a prefrontal lobotomy", but really a nitpick.

I use 5-40 year round. However my choice / brand of oil has come under some scrutiny by The Forum as of lately. Maybe it's time for me to rethink it.

Gradation is fine but nobody ever talks about API / JASO characteristic.

May I ask you to expound on that?

https://www.bardahl.it/specifiche-lubrificanti-moto/

HOW TO CHOOSE THE RIGHT LUBRICANT FOR THE MOTORCYCLE
07/19/2017

Specifications of 4-stroke motorcycles and 2-stroke engines:
A specification is an abbreviation that provides information on the quality characteristics of the lubricant and its intended use. Each specification is associated with numerous tests (engine tests and laboratory tests) that the lubricant must pass to guarantee certain minimum performance requirements. The most common institutes that issue specifications for motorcycle lubricants are:
API: American Petroleum Institute
JASO: Japanese Automobile Standards
ISO: Standardization organization of the industrial organization

API specifications
The API specifications define three categories of lubricants identified with a two letter abbreviation. The first distinguishes the intended use: S: petrol vehicles for 4-stroke engines C: diesel vehicles T: petrol and diesel vehicles for 2-stroke engines. The API specifications for lubricants suitable for use in 4-stroke motorcycle engines are classified with the letter S. The letter following the first is progressive and corresponds in alphabetical order to the last phase of passing the specification of a specific lubricating oil or level of performance and protection. API SM is superior to API SL and so on. The API specifications for lubricants suitable for use in 2-stroke motorcycle engines are classified with the letter T. The letter that follows the first is progressive and corresponds in alphabetical order to the last phase of passing the specification of a specific lubricating oil or level of performance and protection. API TC is superior to API TB and so on.
Specifications JASO
The JASO classification is essentially based on the ability of the lubricant to allow the correct adherence between the clutch discs so that the driving torque can be transmitted from the engine to the gearbox without slipping. Through the measurement of 3 indices, DFI-SFI-STI, which evaluate how the transfer of the torque takes place in conditions of dynamic friction and static friction and the speed with which the transfer takes place, the lubricants can be classified into
JASO MA allow a high friction (suitable for wet clutches)
JASO MB allow less friction
Since the first issue of the JASO specifications, the MA class has been further divided into two classes, and will allow motorcycle manufacturers to request MA1 or MA2 class lubricants on their engines according to the greater or lesser ability of the clutch to control slipping. The lubricants passing from the three categories MB, MA1, MA2, offer progressively better anti-slip performance. Lubricants with JASO MB specifications are now starting to be requested by manufacturers on CVT automatic transmissions. motorcycle oil specific jaso
ISO specifications
The ISO classification embraces the JASO one and introduces further stricter tests that lubricants must pass, especially in terms of anti-pollution capacity and low smoke. motorcycle engine oil ISO specifications

🌈 Thank you Attila. I am pretty sure the rest of the forum appreciates your input as wel.l

I pay particular attention to JASO specs for two-stroke oil.

High-quality, low-soot oil is the only reason two-stroke engines are still available in the US at all. (That and, I suppose, catalytic converters, that I am not certain exists on my 2009 two-stroke.) They are amazing compared to the stuff we were using in the 1980s, when my trusty Honda Spree needed an exhaust cleanout every 1500 miles and suffered from obvious performance issues for the last 200 miles of that interval. Two-stroke outboard engines struggled with similar exhaust blockages due to soot and carbon buildup. Hardly anyone even talks about doing that maintenance any more. I had a shop handle mine, but apparently the home remedies involved cooking a muffler in a campfire or soaking its internals with oven cleaner.