Gear oil vs two cycle mixing oil

[railfancwb]

Suspect this has been addressed many times, but cannot find it...

My Vespa P200e wants SAE 30 plain oil for mixing with gasoline - as do my other Vespas. It wants 90 weight gear oil for the transmission.

I have read that "they are the same" and "they are different".

I changed the oil in the gear box over the weekend, using 90 weight gear oil. When the engine is first started (cold start) gear shifting is very difficult. After it has warmed and several shift sequences have taken place, shifting seems normal. Oil level seems correct, just wanting to run out the uncapped fill opening.

So I am thinking maybe "they are different" is correct and I should have used the same oil I mix with gasoline. Here are the choices at hand, from stateside Walmart.



So is there an authoritative, definitive answer? Are they the same or different?


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[mick1]

Never heard of the SAE 30 being used as 2 stroke oil.....that's the gearbox oil, as recomended. Not sure what code/spec' the 2 stroke oil is but it needs to be able to mix with petrol and not seperate, which most normal oils will do.

[fluff34567]

You will have to order online... Walmart isn't the best place to go tbh.

[Scooterdude]

I think there is a bit of confusion here with oil, on the running in sticker on my Lambretta for example it states SAE30 engine oil for mixing with the petrol and bearing in mind all this was the norm over 50 years ago times change and with the advent of dedicated 2t oils things have changed for the better.
I would say use a decent semi synth from Silkolene castrol Rockoil or one of the other big brands. Personally I've started using Groundsman 2t as it's cheap as chips and has a very decent spec, also that Eden fella uses it in an iron cylinder and does many thousands of miles all over Europe so for me that speaks volumes.
A big problem with using SAE30 engine oil as premix is that it will quickly coke up your cylinder and exhaust.

Regarding the gearbox oil, if the 80 or 90 st is proving to be to viscous I would use something like Silkolene medium gear oil, they also do a light version.

Hope this helps you.

[Minority]

Don't know about Vespas, but "EP" gear oil is considered a bad thing for Lambrettas. ST90 is recommended. The GL5 designation is also bad it seems, something to do with attacking any bronze bushes in the transmission system.

[railfancwb]

After about 100 miles I drained the SAE 80W-90W from the transmission and replaced it with standard non-detergent SAE 30 motor oil. Initially I did this because shifting gears was almost impossible until running had thinned the oil.

Getting rid of the questionable additive is a bonus.


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[Scooterdude]

So you've drained your gearbox of gearbox oil and replaced it with straight 30 motor oil? Oh dear....

[fluff34567]

Why did you use 80w-90w in the first place? And why are you putting engine oil in your gear box ?

[shocky]

So you've drained your gearbox of gearbox oil and replaced it with straight 30 motor oil? Oh dear....

I don't see the problem I've used sae30 in all my vespas and lambrettas for over 30 years including 240,s and ts1

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[Scooterdude]

So you've drained your gearbox of gearbox oil and replaced it with straight 30 motor oil? Oh dear....

I don't see the problem I've used sae30 in all my vespas and lambrettas for over 30 years including 240,s and ts1

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Good for you mate, good for you..