High quality (UK manufactured) coil valve springs to fit the first Norton OHV models manufactured 1924 - circa 1929, and also the first Walter Moore CS1 models 1927 - circa 1928. These models identifiable by having a smaller and more deeply conical type top spring cup than the type that followed in 1929. They have a smaller outer diameter than the next generation of springs that followed in 1928-29 (and there may have been a short period of overlap - possibly the new type being fitted to just the CS1 models and the smaller type still fitted to some OHV models).
They are identifiable from the larger springs thats superceded these (on OHV and CS1 models) in approximately 1929 - by having an outer spring OD of 37.3mm and an inner spring OD of 23.5mm. the 1929 onwards springs are wider than these
Spring Length: The length of the Outer Spring is 45.7mm and the inner spring length is 35.4mm. Please satisfy yourself this length is correct for your engine and valves - as I am told by 1920's experts there may have been a longer type, and regardless of that - some owners may have also fitted slightly longer valves than the original valves these springs were intended for (but we know these are original Springs for Norton OHV engines from their packaging, and they have been fitted to original genuine early type cups - so they will have been fitted to some OHV models of that era!!).
PLEASE NOTE BEFORE ORDERING: These springs are intended for the first 'conical' type cups made from 1924-@29. We do not currently manufacture the cups for this early type. The cups we offer (Item 1029) are for the 2nd generation type introduced circa 1928. Do not order those cups if intending to fit with these springs. Email us if you require more information
Price is for a set of 4 springs (i.e. enough for one engine)
Update February 2023: Please note that the length of the outer springs of this spring set are @44mm long. We mention this because we have had feedback from a customer with an early 1928 Walter Moore CS1, which was fitted with this early 'small' type spring (as supposedlly the first CS1 models were) but his engine may have been fitted with later (ES2) valves - and these springs were too short for that particular bike. It is difficult to be definitive about if the early CS1 models fitted with this smaller diameter 1920's type spring also had shorter valves - but please bear this in mind. If you do have a CS1 (or 1929 ES2) fitted with this early type of valve - and the length of the outer spring is longer than 44mm we would be interested to hear from you - on email@example.com. Thx.
Hard to believe - but to make these springs, we were able to borrow from a collector friend a 100 year old, 'New Old Stock' genuine set of Terry's valve springs - still in the remains of their orgiinal box! - see accompanyning photos. As an aside, we have many original sets of Terry's valve springs we use for patterns - but I have never seen Terry's packaging as old as this type, and with different colouring and branding to the later types that followed. However, it is just possible to confirm they are indeed for OHV Norton models of the earliest design, and alongside them you can see original 1924-29 type top cups. As always, we have had these valve springs replicated to the original dimensions and design by our top quality UK spring manufacturer.
This design of valve springs (with very small inner spring, when compared to most OHV and CS1 coil springs that followed) was fitted to the very first design of 'Flat Tank' OHV Norton models from 1924 to approximately 1929 (it is hard to tell exactly which year they swopped over to the later and larger spring - as Spare Parts lists for circa 1928-29 were seperate for SV/OHV and ES2/CS1 and supplements were later added - it may be some Model 18's continued to be fitted with the earlier spring types, while ES2 moved to the later design first.
This first design of valve spring and deep conical cup were also fitted to the earliest Walter Moore CS1 models - probably 1927 and 1928. But if you have a CS1 model - please enquire with us if you are not sure - firstname.lastname@example.org, as we have spoken to CS1 owners with both types fitted - and we gather many owners of earlier machines may have switched to the later design at some point in the distant past!
Please Note: This type of spring - and the conical top valve cups that were used with them, are of smaller diameter and length than the later type of spring/conical cup that followed in approximately 1929 (see Item 1029 for the the 1929 onwards conical cups and Item 0966 for the valve springs that were fitted to that later design) - so although this distinctive 'Conical' style top cup is a good identifier - it should be noted that there were two types ftited between 1924-1932 . . . when ordering it is important to ensure your engine is fitted with this earlier type, as I am told it was not unusual for earlier Pre-1930 OHV and CS1 models to have been retrospectively fitted with the later and 'beefier' valve springs and larger conical valve springs cups.
We are pleased to be able to offer this spring, particularly as it was patterned on genuine period valve springs - and as I write this listing in November 2022 - I can say that these have the earliest Norton Part Number we have ever referenced - that being Part Number 1074-1075, as listed in the 1925 Norton Spare Parts List! (and picture of a Model 18 from the factory photograph of that 1925 year is shown)
Final Note on these springs: We do not currently have plans for making the distinctive cups for these early type springs (although we do nmanufacture the 1929 onwards type) .. . but if you do require them, contact us, we may consider making them in the future if enough demand