This Rocker Adjuster and Tapered Locknut are to fit Flat Tank OHV Models (i.e Model 18 and Model 19) between approximately 1926 and 1929 - the distinguishing features of this type being that this type screwed into the front of the OHV Rockers, and had a 'ball' profile at the end - that fitted directly into the top Pushrod cup - see the period photographs that accompany this item listing.
We have CNC manufactured this type of rocker adjuster using an original 1920's Norton item as the pattern - and replicating all dimensions as per the original. They are made from case hardened EN32B, but like the Norton originals - the threads are 'painted off' before hardening, so the threads do not go brittle in the hardening process. The reverse end of the adjuster has a square head milled into it, for adjusting tappet clearance iwth a small spanner - again replicating the dimensions of the original Norton square. It should be noted that the thread of these early type Rocker Adjusters (and the slightly later adjusters we also offer - Item 1121 and 1122) is actually 9/32" x 26tpi BSC thread - as per the original item.
As well as teh actual hardened adjuster, we also include the correct profile locknut - which has a slight taper on one end - which should fit into the original Norton OHV Rocker recess. The other end has a minimum chamfer. Again, this locknut is copied from an original period Item - but unlike the original, ours are CNC manufactured from stainless steel - to prevent rusting. It should be noted that on the original 1920's nut that we coped - we noted that the depth of this nut was fractionally shallower than the original 1930 onwards original nut we also manufacture (Item 1123) - but the difference is minimal, and I suspect either type could be used.
Each Rocker Adjuster and Locknut is supplied assembled with high melting point grease applied - to prevent corrosion in storage.
Price is for a single adjuster and locknut (i.e. 2 parts) - Therefore 2 of these are required per engine.
Backgound: This distinctive 'Ball Ended' rocker adjuster were fitted to 1920's Flat Tank OHV Nortons. I am not an expert myself on flat tank Norton's - but from what I can see in original Photos and Spare Parts List's (and talking to helpful customers with more Flat Tank knowledge than me!) - I beileve the very first Norton OHV in 1924-1925 may have had a slightly different design of Rocker Adjuster - and this type were probably not fitted until approximately 1926.
Therefore if you have a very early OHV Norton before 1926 (lucky you!) - then please confirm for yourself if this type of adjuster will fit your engine. I believe the very first engines had an adjuster with Part Number 1027 (i.e. earlier than the design listed here) - so you will need to check your engine for yourself (but if you do have an earlier design - we would be interested to see a picture, and get dimensions from you, thx).
We believe this adjuster was introduced sometime around 1926 and it was still listed in the Norton Model 18/Side Valve Spare Parts List of 1929 - by which time the Walter Moore CS1 and OHV ES2 models were showing the later Rear Rocker/Flat Pad (our Item 1121) design of rocker being fitted. Therefore there looks to be a short period where both types of rocker adjuster were being offered concurrently - but on different models.
Please satisfy yourself this adjuster type is correct for your model - but you can email us on sales@racingvincent.co.uk if you require more information.
Update October 2022: As you can see, these items are not cheap - but reflect the amount of time we have spent checking originals, and setup on very small batch's (as well as greatly increased material and hardening prices in recent times). Hopefully you will understand that the price reflects the small batch quantities of these we manufacture. And of course - original examples are now almost impossible to find!