Technical Engine Id

[Tinyotim]

Today I found my engine number on my 1975 500R and it says 126? (see pic) is this normal for the 1975 model or has it been swapped at sometime?
Could someone tell me how to tell what size it is please so I know definitively what settings I should be using etc
Your help much appreciated.

 

[Toshi 975]

That is exactly the right prefix for a 500R engine, 126A indicates a 594 engine which was exactly the same as the series 1 126 which was launched around the same time. However to make the new 126 stand out more Fiat detuned the restricted 500R by fitting a Weber 24IMB carb.
An engine with a 126A1 prefix is a later 650cc

 

[Tinyotim]

That is exactly the right prefix for a 500R engine, 126A indicates a 594 engine which was exactly the same as the series 1 126 which was launched around the same time. However to make the new 126 stand out more Fiat detuned the restricted 500R by fitting a Weber 24IMB carb.
An engine with a 126A1 prefix is a later 650cc

Thanks very much