How to determine the age of your Solex by using the Q & A sections below
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 by the factory 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 down the manufacturing period.
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 (it it should need one) 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: email@example.com.
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.
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.
Engine type approval (homologation) dates – This is not the date the engine or the Solex was manufactured!
Early 45cc - front
Later 45cc - front
Later 45cc - rear
Typical rear stamping - 1010
Cyclomoteur 2200 - front stamping
Cyclomoteur 2200 - rear
Typical engine number stampings found on Cyclomoteur 3800 engines.
5000 / 4600 V1
Hungarian S 3800
Examples of engine numbers stamped onto plates and riveted to the crankcase.
*IMPORTANT - See the note below for special information relating to the series of engine numbers specifically stamped onto plates and then 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: www.solexmillenium.fr
* Further information regarding engine numbers stamped onto plates and then riveted to the crankcase:
After Motobecane took over the Velosolex company at the end of 1974, they reused serial numbers in the 3xxxxxx, 4xxxxxx, and 5xxxxxx ranges. Fortunately, they stamped these numbers onto small metal tags that were riveted to the engine instead of being stamped directly onto the crankcase.
These numbers are not represented on the vast majority of online charts. However, there is a French website dedicated entirely to the Motobecane Solexes and you may find your engine serial number range on the charts on this page:
This information was added in February 2021 by Paul G.
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 appear to have a frame number but 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. Since this section was written, the U.K. law regarding the M.O.T. test has changed to be a rolling 40 year exemption. However, a Solex younger than 40 years will still require and M.O.T. and will still need a frame number / V.I.N. (Vehicle Idenetification Number) to satisfy the tester. 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. OK, so my Solex is over 40 years old and is M.O.T. exempt but does it still need a frame number / V.I.N?
A. Yes, again. Although the Solex will not have to satisfy an M.O.T. tester, it is highly likely / probable that the D.V.L.A. will require the Solex to be inspected on their behalf by one of their nominated inspectors before they will issue a V5C registration document (logbook). Also, you will need to supply a frame number / V.I.N. and a photograph to your chosen D.V.L.A. approved organisation beforehand when requesting a dating certificate.
Q. What should I do to put a frame number V.I.N. onto the Solex?
A. Probably the simplest and easiest solution is to use a set of number punches and to stamp the number in a convenient position. Previous experience of other members dealings with the D.V.L.A. seems to favour using the engine number. (Indeed, this was the practice used by the D.V.L.A's predecessor in the 1960's and early 1970's when a new Solex was sold in the U.K. There are many instances where a new Solex from that period was issed with a log book and the engine number has been used for the frame number.) 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 shown above for the S 3800, 4600 & 5000 models) is another place but be warned, it does come with the risk of denting the frame in that localised area when the number is being stamped.
Q. What are the alternatives to stamping the stand bracket or main frame?
A. Here are some suggestions:
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 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 are 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 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 an approximate date of manufacture?
A. Many of the features and seasonal upgrades on a Solex will help to establish or confirm a fairly accurate manufacturing date. The website of Marc Deschamps (www.lesolex.com) 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 the S 3800 models 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.