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Forum Home > How to DETERMINE THE AGE OF YOUR SOLEX. > Use the Q & A sections to find out.

Paul G
Site Owner
Posts: 2433

One of the most frequently asked questions (F.A.Q’s) on the Forum is: ‘How old is my Solex?’ Fortunately, for many years the Solex engine numbers were issued and are well documented. From 1946, through to the mid 1960’s, the production start number and date is recorded along with production numbers commencing each January of the new year. Although later manufacturers did not make their engine numbers known to the same extent, several groups of Solex enthusiasts have been steadily collating this missing information. This means that the age of Solexes produced after the mid to late 1960’s can be reasonably accurately dated using the ever increasing databases of such information. However, this method has its own unique problems as it is known some series of engine numbers were re-used, and some series of engine numbers were used on more than one model. Dating then becomes more difficult and has to rely on other features to be found on the Solex (handlebar styles, lighting types, throttle and brake controls, wheels, etc.) to help with narrowing the manufacturing period down.

In an effort to help new U.K. owners through the ‘Solex dating’ problem, the following has been devised as a series of F.A.Q’s with answers. However, it is beyond the scope of this article to be able to cover all the different worldwide variations and so it is confined mainly to getting an imported Solex through the necessary requirements of M.O.T. test and the D.V.L.A. with a view to getting a registration number allocated.

Note: If, after reading the following you are still unable to determine the year of manufacture of your Solex, Brian Solex has kindly offered his extensive Solex knowledge and assistance. When contacting Brian, you should provide the engine number, the frame number (if there is one), and (ideally) one or two good quality pictures of the Solex. You can e-mail your request for assistance with the information directly to:

Q.   Why do I need to quote my engine number when asking for technical information on the Velosolex Club U.K. website? Isn't my Solex date of manufacture clearly cast into the engine crankcase?

A.   Not so! There are two dates to be found cast into the later crankcases: 25.10.1962 and 14.3.1966. Both dates simply refer to when the Cyclomoteur was ‘homologated’ or approved for use on French roads. The only way to accurately date the Solex (assuming it still retains its original engine) is by the engine number.


Engine type approval (homologation) dates – not the Solex manufactured date!

Q.   Where can I find the engine number?

A.   There are two locations: Usually, it will be found at the back of the crankcase. The numbers will either be hand-stamped directly into the metal or, on later engines, they may be found stamped onto an aluminium plate which has been riveted in position. Other engines, such as the 45cc*, 1700 and 2200* had their engine numbers stamped at the front of the engine behind the fuel pump.

*45cc engine numbers started off being stamped at the front, behind the fuel pump, before moving to the rear of the crankcase. The 2200 engines appear to swap from front to rear locations regardless as to whether the model is a V1 or a V2.


Early 45cc – front                                         Later 45cc – front                                        Later 45cc - rear


Typical rear stamping – 1010                      Cyclomoteur 2200 – front stamping                    Cyclomoteur 2200 – rear


5000 / 4600 V1                                                                 S 3800                                                     Hungarian S 3800

Typical engine stampings found on Cyclomoteur 3800 engines


Examples of engine numbers stamped onto plates and riveted to the crankcase

Q.   What does my engine number tell me?

A.   By referring to the chart below, you can see when you engine was made. This is also taken, as a general rule, to be the same date the Solex was made.

Solex engine numbers and production dates.

Information generally based on figures taken from

Q.   Does my Solex have a frame number?

A.   Not always. Frame numbers appear to have been somewhat hit and miss. Many of the earlier Solexes have frame numbers. Many of the later Solexes may only have a frame number if it was a territorial requirement. i.e. Solexes for the French home market did not require a frame number in the 1960’s but export models did. Later manufacturers like Motobecane and Impex seemed to have followed the same trend to a greater or lesser extent.


 45cc and 330                                                 660 through to S 2200                              S 3800, 4600 and 5000

Q.   My Solex definitely does not have a frame number in any of the reported positions but to get it registered in the U.K. I have been told it must have one. Is this correct?

A.   Yes. Referring to ‘The M.O.T. Inspection Manual for Motor Bicycle and Side Car Testing’ issued by V.O.S.A. (Vehicle and Operator Services Agency) for M.O.T. testers (downloadable from the Solex reference section) in section 6.3, 'Registration Plates and Vehicle Identification Numbers,' on page 3 it states the tester must:

5. Check that the machine is permanently displaying a legible Vehicle Identification Number.

This can be either

  • on a plate secured to the frame of the machine, or
  • stamped or etched on the frame of the machine.

Q.   What should I do to put a frame number onto the Solex?

A.   Probably the simplest and easiest solution is to use a set of number punches and to stamp a number in a convenient position. This could be the same number as the engine, or a telephone, or a birthdate, or anything else you want! In the writers opinion, stamping the frame number on the front face of the stand bracket under the main frame is a good position. It is reasonably accessible and provides a good solid face onto which the number can be stamped. Using the top of the main frame next to the steering head, as for the S 3800 models onwards, does come with the risk of denting the frame in that localised area when the number is being stamped.


1) One or two companies can be found on the internet selling blank V.I.N. (Vehicle Identification Number) plates. These can be stamped with the number of your choice and then ‘pop’ riveted onto the frame at a suitable location. (Enter ‘Motorcycle V.I.N. plates’ into the search engine and then click on images to find a supplier of blank plates that can be stamped. Prices around £10.00 - £15.00)


2) A cheaper alternative to a dedicated V.I.N. plate is to do a search for ‘blank Mini engine number tag.’ These were typically used on the B.M.C. ‘A’ series engines. Prices around £2.50 - £3.00. Comes with the rivet holes already drilled!

3) Stamp your own number onto a plain strip of aluminium and then simply rivet it to the frame.

Q.   My Solex does not have a frame number and I am not sure if the engine used to date it is original. Is there any other way to find a manufactured date?

A.   Many of the Solex features and upgrades will help establish or confirm an accurate manufacturing date. The website of Marc Deschamps ( has an excellent ‘Chronologie’ section covering Solex modifications, with pictures, to assist with dating. A publication (in English) to be found on the internet and available to download as a PDF on the Velosolex Club U.K. website is ‘The Velosolex 3800, A detailed pictorial model history.’ This is a compilation of the Marc Deschamps information, translated into English, and covering S 3800’s produced between 1966 and 1988.

The dating of some Solexes can also be gauged by using the wheels. A simple single or double digit month and year code may be stamped onto the wheel rims. Obviously, this is only the date the wheel rim was manufactured but it may be useful in gaining an overall picture of the Solex. The examples below show ‘1’ and ‘64’ within the diamond and ‘10’ and ‘97’ stamped alongside the wheel information.


Wheel rim manufactured dates – sometimes within a diamond, sometimes just stamped onto the rim.


Paul G

"Getting there ....... slowly"   

September 14, 2015 at 2:41 PM Flag Quote & Reply

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