Sorry to say,Excelsior did make a 600 SV in 1935.
Pouls model is a model E13 with the correct engine it left the factory with.
The number 10 dont show the model if you think that.
regards
Hello Poul,
Yes, E10/90 identifies a 1935 Excelsior with a twin port OHV JAP engine. Excelsior did not list a big side valve in 1935. Probably some one changed over engines when the original wore out. Side valve JAP engines are much easier to find than OHV and much cheaper. It was an easy fix back when bikes like this had no value. It is also possible someone asked the factory to fit the side valve engine from new. It was very easy for a factory like Excelsior to fit a different engine if the customer paid for it.
Most probably it was just a cheap engine changeover.
The bike was fitted with an Albion four speed heavyweight box from new. It sounds like yours is the original box.
You will find very little information printed by the Excelsior factory. This doesn't matter as the bike is built up from proprietary components. You just go direct to the supplier, J.A.P engines, Albion gear box, Webb forks and so on.
The Vintage Motor Cycle Club Library has plenty of information to get you started. You can find them at vmcc.net.uk
Best of luck.