Two Stroke Oil

[MightyGem]

Which do you use? Mineral, semi synthetic or fully synthetic and why?

I use fully synthetic on the assumption that it will keep any carbon deposits to minimum. Am I correct in my assumption?

[MilanoMod]

Stock SX200: 3-4% of anything. She isn’t picky.

RB22: 4% Motul 710. It’s what they recommend so I cover my ass a bit if something goes wrong.

[MilanoMod]

Oh -

The SX gets deposits I clean every couple years, the RB is pretty clean so far. Maybe it’s using full synthetic but it could just as well be that the RB runs hotter and burns off deposits or runs leaner

[Toddy]

Groundsman rock oil

[Tractorman]

Groundsman rock oil

Totally agree.

[Burnside]

Groundsman rock oil

Same. It's cheap and it does what you need it to do so why spend more?

[Warkton Tornado No.1]

Not all Lambretta engines need the same petroil mix. Nowadays, with the reed valve engine, it needs to be pointed out that if the inlet has an auxiliary transfer, there may be some truth in the fact that the big end may miss out on the amount of lubrication that it might otherwise receive.

So, my apologies for introducing what may be a 'red herring' but the fact should be borne in mind. Also, if an 'uprated crankshaft' for a specific kit is sold with the undertaking that a specific oil/mix ratio is mandatory, then I guess you should comply. Confirms to my mind that not all 'uprated' crankshafts are equal......

That said, the last engine I completely rebuilt is extensively ported including a huge slot to the inlet side of the skirt feeding into/out from the inlet port. The passageway literally crosses the inlet both up & down. The barrel was a 70 mm Ebay scrapper that I thought I could salvage without replacing the skirt OR plating which was slotted both sides by the engine throwing it's rod. Seem's I was right.......Such an extensive tune to start first half-hearted kick amazed me. It also flies like sh1t off a shovel.

Yet, I use only 2% Exol Optima racing two stroke with super unleaded in that 70 x 60 engine & a Rapido 71 x 61. Neither engines are high compression, both are precisely 1mm squish with matched head/crown profiles & both run Vega/J/Rayspeed fans with closely fitted cowlings to prevent cavitation.

I don't know of any other oil specific to 'racing, air cooled two stroke engines' nor as cheap as my last lot (strictly cash deal, no paperwork from the local distributor) @ five litres for 15 quid.

If I were to build a race only engine with AvGas, I would up the ratio to 3%. Exactly the same mix ratio as when last racing using Rock Synthesis 2.

"Ya' pays ya' money & makes ya' choice'

[HxPaul]

Groundsman rock oil +1

[YAMLAM]

Another Groundsman fan here.

[shamrockexpress]

Oregon for me, its a semi synthetic chainsaw 2t from canada it has all the letters JASO FC FD , API,,,,,,,,etc