Gary Ellis, owner of Minsk, Voskhod and Planeta 350 (Australia)
In answer to your 2 stroke oil mix question 25-1 with a good mineral 2 stroke oil, stay away from semi and full synthetic in old style 2 stroke engines!
Rod Knight (Australia)
I don’t ride my Jupiter very often, but it receives sufficient use to keep it in good running condition. Like you I’ve always used a 25:1 fuel/oil mix for all my two-stroke engines, which dates back to my very first motor scooter in 1963.
I could perhaps have changed this to a leaner 30:1 mix when modern ashless two-stroke oils became available as they have superior lubrication properties, but decided not to. Please stay with mineral oil rather than be tempted to use a synthetic as these old engines were designed to use mineral oil! My ‘learned friend’ in Stanthorpe unwittingly destroyed a decades-old chainsaw engine after he’d been advised by an “expert” to use a synthetic oil in it.
And while I can understand Catweazle’s reasoning to use a leaner 33:1 blend I’d stay with 25:1 for the reasons you’ve stated!
JD to Rod (That might work in Europe’s colder climate, but in Oz?)
Rene Willemsen (The Netherlands) Chairman MZ Club
As with everything in life, opinions on this subject vary.
In the 1970s, the DDR magazine Kraftfahrzeugtechik conducted an investigation.
A test was carried out with the usual Russian oil as the basis and with Austrian oil as the basis for the production of two-stroke oil. The prescribed ratio and half.
After a while, the piston and cylinder were assessed. Lean driving with the Russian base caused damage but not with the Austrian. Because the latter was not or hardly available in the DDR, the old proportions were maintained.
At the end of the 1980s, MZ stated in the workshop manuals that if synthetic Castrol biolub was used, the MZ ETZ250 was allowed to lubricate 1 in 100.
I myself have driven for a while on the Ecomaxx petrol in the ratio 1 to 80. (Note: Ecomaxx bike fuel 4 and Ecomaxx 2 stroke mixed 1:1)
In my MZ RT from ’61 I use the Ecomaxx 2 stroke that is mixed 1 to 40 instead of mixing 1 to 25
The opinion, extra lubrication is better is not correct either. You get stuck piston rings and that’s not good either.
Siegfried (The Netherlands) UDCN member
Where the Jupiter could handle 1 in 50, a 1 cylinder certainly cannot.
I recently found out with my Izh 49.
They also write 1 in 25 for that, you will find that after googling.
I usually search in German. I like 1 in 30 myself. If you get too much smoke, take a look at Triboron.
With regard to the lubrication, now know why MZ can have 1 in 50.
Found info showing that this has to do with material quality.
That is just a little different with Izh, that’s why they have to be lubricated more richly.
Fredrik Rosengren (Sweden)
All IZH shall use 1liter mineraloil 20W50 in the gearbox, 3% oil mix in the fuel with synthetic two stroke oil.
Note: a 3% mixture = 1:33