Hi Steve,
If your reading this on the website first, please check your Junk / Spam email folders for my reply.
Frame number 150LD ******* (Located on the frame and not the engine) – Your Lambretta is a 1956 MK2.
If you applied for a dating letter from the BLA (British Lambretta Archives), based on this number being seen on the frame, the dating letter would state a build date of 1956. This should be the same, if you applied to the LCGB (Lambretta Club Great Britain). This assumes your located in the UK and were to use one of these clubs for a dating letter to aid in UK vehicle registration.
Website – britishlambrettaarchive (BLA)
LD 150 (Mk 2) 150LD
1954: 105,001 – 105,442
1955: 105,443 – 157,801
1956: 157,802 – 212,350
The BLA also have another website called LambrettaFrameCheck that can also confirm this.
The oil to fuel ratio, I will need to point you to the website to read. Here is the link (You may need to copy and paste the link into your browser)
Fuel Mixes and Oils
Some options to start you off may include
4% Rock Motor Oil SAE 30 (Note – not SAE30 Lawnmower oil – also seen as Groundsman). 4% Rock Motor Oil SAE30 is a recommended solution in the LD 1950’s manual. It can also found online as Rock Oil Classic
Alternatively a 3% Rock Oil PP2 Semi Synthetic solution.
Oil and Fuel / Gas Mix
It is important to understand that the oil and gas fuel ratio can differ depending on some factors. Some of these can include if’s it’s had a partial or complete rebuild and what type of oil you use (Classis / Semi or Full Synthetic solution). They all have pro’s and cons. Search online for “Synthetic oil vs. conventional oil” and “benefits-to-sticking-with-conventional-motor-oil” if interested and read a few of the articles.
Plain bush or roller bearing can also make a difference as well as how often you intend to use your Lambretta.
As a starting point though, you may want to consider the information above and please do read the information on the link I have provided in this email (Also found under the website on the page General Info / Fuel Mixes and Oils), to give yourself a better understanding in this area.
Although the website is responsive, it is best viewed on a device such as a PC / MAC
All the best and have a good weekend
John
Lambretta Journey