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Collection, Preservation and Display of Old Lawn Mowers

Two stroke oils


ive searched the site on the subject of two stroke Fuel. There seems to be plenty of options. I'm restoring a Standard with a Villiers MK V1 A engine. 16-1 is manual spec. I've read about altering this to take into account modern petrol and their additives. Has anybody made this adjustment if so can you share please thanks



wristpin Wed, 06/01/2021

Endless debate on that subject but mainly regarding the physical properties of the available oils rather than those of the fuel. . Most of the old two-stroke engines with a 16:1 recommendation came from an era when there were no specific two-stroke mixing oils and were probably running with plain bearings and rudimentary crankcase seals and running at less than 3000 rpm. The recommended oils would have been a straight non detergent SAE 30 or 40 motor oil such as Castrol XL. For those engines I still use a similar oil now branded as a “Classic two- stroke  oil” -  basically because the “ thicker mix”  suits the construction of the engine.

The down side of the original motor oil 16:1 mix is a greater likelihood of the plug fouling and the exhaust blocking with carbon. To some extent this was addressed with the introduction of specific mineral based two- stroke oils and later by semi synthetic based oils and finally by fully synthetic oils for engines now running in excess of 14000 rpm .

So for your Standard  I would still run at 16:1 using a non detergent SAE30 motor oil or one of the Classic Motorcycle mixing oils from the likes of Millers or Morris Lubricants which are probably blended to take account of current ethanol adulterated pump fuel. 

“ Old oil for Old Engines”    


Adrian Wed, 06/01/2021

"The down side of the original motor oil 16:1 mix is a greater likelihood of the plug fouling and the exhaust blocking with carbon."

I suspect most of us could live with the risk, certainly of the latter issue, as we are running the things for nothing like the length of time they were ran for in their heyday.

Mind you, when I took my Standard apart first, despite the evidence of regular visits to service depots, there was so much carbon in the silencer it literally blew lumps of oily crud out of the pipe when running, and I could ladle the gunge out with a spoon - there must have been about a pound of it in there!

DJD Wed, 13/01/2021

May I chime in with my twopennorth?

I run two stroke motorbikes as well as having had a tree surgery business for winter work to help stay in business, when I ran five Stihl and Husqvarna saws etc. I used to buy a gallon of Central spares own semi synthetic oil about twice a year and mix up all my two stroke at roughly 45 or 50-1. I run BSA Bantams and MZ bikes too, but everything seems to go well and thrive on this mix. A 100ML oil bottle is filled from the gallon container and emptied into the gallon (or should I say 4.55555 litres) can, what could be simpler?

It's a long and often long debated topic, most two stroke club forums have a long list of members' views!

The upshot of several I found, was to find a system that suits both the bike and yourself and stick to it.