Listed here are reproduction parts to fit Amal Remote Needle (RN) carburettors. These carburettors were fitted to the racing versions of SOHC (Manx) Nortons from the late 1930's, through to about 1951 when they were replaced with the fitting of the GP1.

In Amals racing evolution, these carburettors were like an interim version of the GP carb, in so much that Amal had realised it would be a good idea to move the needle away from the choke area, so as not to obstruct the airflow, so giving the name 'Remote Needle'.

In practice, it was found that the route for the fuel flow from the needle was not perfect (so I am led to believe from the literature I have read) and therefore they were more fickle to tune than the more common TT carb. However, they were found to give better results on 'out and out' fast circuits, which presumably the Grand Prix bikes were more likely to encounter. Clearly, Amal's thought they were on the right track, because the GP1 carb was similar in concept, however the fuel routing was improved in design.

As an FYI for Manx Norton owners - the Amal RN carb was eventually superceded by the first Amal GP Carb - which was the GP1 version, but the GP10 variant - where the '10' referred to the throttle slide bore diameter (approx 52/53).  Then this was superceded with the GP5 variant on Shortstroke DOHC Manx Nortons.  We also offer GP5 slides in our GP section.  The GP10 variant is now quite rare - but email us for details as we occasionally have these slides as well.

As a footnote to this, I remember when I started racing in the 1980's that RN carbs were quite common on peoples shelf's because they were considered rubbish for short circuit racing, and no-one wanted them!

I certainly remember turning up my nose at a couple of them, even though they were often cheaper to buy at Autojumbles than a comparitive Amal TT carb - - - not so now! There seems to be very little information available for Remote Needle carburettor, and the parts specific to RN carburettors are now extremely difficult to find.

This section offers some of the parts specific to the RN carb and in almost all cases - we have used original Amal RN parts as patterns.

Please note though, that these parts will be comparably far more expensive than the TT parts, as I am having them made specially in much smaller quantities than the TT parts.

Castrol ValveMaster Plus - Lead Replacement Plus Octane Booster - 250ml Bottle.  If your Norton (or any other classic motorcycle) has not been fitted with new 'unleaded' type valve seats, then using modern unleaded petrol will lead to excessive wear of your valve seats.

Castrol offer Valvemaster Plus to combat this problem - just add a small measure of this liquid to your fuel tank each time you fill up and you will effectively be changing your 'unleaded' specification to 'leaded type - and therefore will protect valve seats.  

Note: Castrol make 2 versions of this lead replacement additive, a standard version, and then this version which also has an Octane booster included.  I always add this version to my British motorcycles - as I want to provide as high as an octane rating as possible to the high performance engines we are running (SOHC Nortons, sports twins etc), to reduce the possibility of pinking.  Therefore I use this in all my classic bikes.

However, should any more encouragement be needed - it is also endorsed by the Federation of British Historic Vehicle Clubs.

This 250ml bottle will treat 250 litres of fuel (1ml to each litre of fuel).  The reason I like this Castrol lead replacement offering over other makes is that the bottle includes a clever measuring device at the top - just squeeze the lower part of the container until the correct quantity of the additive fills the top measuring holder, which is graduated with the different quantities of fuel you are filling your tank with - simple!

Always read instructions before use.

Driven Defender and Booster - Lead Replacement Plus Octane Booster - 295ml Bottle.  If your Norton (or any other classic motorcycle) has not been fitted with new 'unleaded' type valve seats, then using modern unleaded petrol will lead to excessive wear of your valve seats.

Driven is a well known specialist American oil company, producting oils and additives for the motor racing industry - and one of their products is this fuel additive that protects valve seats on older style 'leaded' engines, as well as increasing octane  - just add a small measure of this liquid to your fuel tank each time you fill up and you will effectively be changing your 'unleaded' specification to 'leaded type - and therefore will protect valve seats.  

This 295ml/10 Fl oz bottle will treat up to 25 gallons (not litres . . . remember it is a US company!) of fuel.  The bottle has graduations along its side, along with a clear plastic area so you can easily see how much additive you  are adding on each fill up. 

I have recently stocked this item because other UK additives have been getting harder to find - and it is supplied by my main racing fuel distributor, so know they can be trusted.  I am using this additive myself now in my roadgoing Vincent and will report back results later in 2018

Always read instructions before use.

This Facsimile is a full and comprehensive catalog, listing good quality reproductions of original Amal specification and tuning sheets for the Amal TT, RN (Remote Needle) and GP competition model carburettors, and also includes a full list of settings for SOHC Norton models when fitted with these models as well as a comprehensive setup guide from period Norton technical guides for these carburettors.  

Price is Each

We also include the most common TT/RN carb settings for Norton 350cc and 500cc carbs, as well as some other useful carb tuning information from period Norton and other tuning experts.

Background:

The TT type competition carburettorwas first produced in the 1920's - before Amal was formed, at that time the company was called Amac - and we include a single page exploded view of that early Amac design in this facsimile.  The carburettor was then updated through the years (some pre-war versions being identifiable as they had the sub-model number relating to year stamped on the flange - i.e. TT27 or TT35), before being developed into the RN (Remote Needle) carburettor - used mainly on genuine competition bikes only, such as Manx's and KTT's, before being further developed into the GP carburettor. 

We also include one of the first of the Amal TT specification sheets (on which the cover shows the amalgamation of Amacs, Binks and B&B to create Amal), from approximately 1934, which also lists and shows pictures of many of the other carb accessories they were making in the early 1930's.  This being from an original I have in my own collection 

This Facsimile brings together copies of many of the original (and rare to find) Amac/Amal Tuning/Spares sheets for these different carburettor types - and as well as giving an interesting chronological account of how they changed - is invaluable for anyone trying to setup these carburettors - as there is a very specific order to do this in for most of the designs.

Then, in the second half of the document we have a section listing the most common settings for TT and RN carbs fitted to Norton SOHC models by year, as well as some common settings for many bikes fitted with Amal competition carbs in the 1950's (from a well known tuning book at the time). 

Finally, we also include a section from one of the period (1940's-50's) Norton technical manuals, written by the then Technical Manager for Norton's - Edgar Franks, on how to setup your road Norton SOHC for TT carbs, as well as a section on racing.

As well as being an interesting Facsimile, it contains a wealth of information for anyone who has a bike fitted with either TT, RN or GP carbs.

Printed on high quality A4 paper, with original documents carefully reproduced (and cleaned up if necessary), with a green card cover and Contents section, this facsimile is of circa 50 pages in total. 

'Remote Needle' type throttle slide and needle holder to fit original Amal 10RN (Remote Needle) type racing carburetter - these been original fitment on most 1937 onwards SOHC (and pre-1953 DOHC)  M30/M40 and Manx models.  Amal RN carbs were also fitted to many other period competition and 'Grand Prix' spec motorcycles - i.e. KTT Velo's and similar.

For Norton Single M30, M40 and Manx Models, the following slide fittings were most normal:

- 500cc Manx and M30 Models: No6 RN Slide (LH type - whcih these are) 

- 350cc Manx and M40 Models: No5 RN Slide (LH type - whcih these are) 

Background and Manufacturing Information:

As can be seen from the photograph's - these slides are actually based on the similar Amal TT slide design, but the slides for Amal RN carb has an additional threaded hole and slight countersink, to hold a special milled brass sidebar, which holds the throttle needle in a seperate chamber alongside the main carb body - which helps reduce the obstruction of air into the engine.

We have the main slides made to the same specification as our TT slides (see Item 0143), but for these we have the addition of a threaded hole in the top face of the slide.  We also have the special RN throttle needle holder manufactured identical to the original design - and original Amal RN needle holder being used as the pattern - these are CNC milled from billet Brass.

Original Amal RN slides used a flush fitting brass screw to fix the throttle needle holder to the slide - but they also had the threaded shaft of the screw 'mushroomed' underneath, and the holder soldered to the slide - once fitted.  Both of these features were to ensure the throttle needle holder did not vibrate loose in service.  As you can see from the accompanying photos - we have made jigs that allow both of these steps to be carried out - and once completed each slide is test fitted on both an original Amal RN inner block and a virtually new (old stock) brass bodied RN Carb body - to ensure smooth operation.

Note: that as part of this necessary manufacturing process - because we have the TT and RN slides 'flash plated' (to stop corrosion of the slide) first - we carefully remove the nickel plating in the area on top of the throttle slide, where the needle holder is to be fixed - to ensure the best possible contact for the solder.  This is purely cosmetic - and necessary to ensure proper solder flow.   

Stocks of this type of slide are limited, so if you need one, we can only advise you order one quite soon . . . as once this batch have gone, it will be at least 12 - 18 months until we makle a further batch - as you can see from the accompanyning photographs - on top of the normal 'TT Slide' manufacturing processes - there are a number of other processes required - speciific to the original Amal RN slide design - which we follow as faithfully as possible.  

Amal RN (and slide/needle design) Background Information:

As far as I am aware the Amal RN carburettor was introduced in the mid/late 1930's purely for competition motorcycles - in an effort to give a less obstructed airflow through the inlet tract - not unlike the Amal Type 27 needless dirt track carburettor (which I used to have fitted to my old Rotrax JAP speedway bike - and was good for full bore, but not much good for any kind of cutover or slow running).  To do this it moved the needle position from in the centre of the main choke area/inlet tract to the side of the carb.  From what I can gather, it had a reputation for being a better carburettor on long GP circuits such as the Isle of Man or Spa (etc), but was a bit more 'fussy' for slow or mid range running on roadgoing sports bikes, which were normally fitted with Amal TT carbs.

What I do remember as a teenager in the 1970's and 1980's - just starting vintage racing at the time, was that the RN carburettor was not considered as desirable as the TT carburettor for fitting to historic race bikes for VMCC (short circuit) racing, as they were considered less flexible - but really I am not sure if this was true or not.  What was probably far more true was that as the slide got worn and let air bypass - it was less easy to find a replacement slide, so more of them were worn.  I think because of this they were often overlooked. .  . and probably many of them thrown away - making them far less common and hard to find today!

I only remember fitting an Amal RN to one of my Norton's once, and that was back to back with a similar bore/condition Amal TT - both setup for methanol.  If I remember correctly - I could not tell any discernable difference between the two.

Those originally fitted to M30/M40 and early Manx Norton models were of the 'Long Neck' variety (as in the accompanyning photograph - note the inlet tract mounting flange extends past the lower slow running adjuster by approximately 1 inch, while 'normal neck' type carbs have the flange abutting this carb and are shorter.  Therefore, this 'Long Neck' variety are (not suprisingly) considered the most desirable and difficult to find.  However, it is possible to fit short neck type - but it is normal to fit a 1" alloy spacer to restore the full Norton inlet tract length.

Please note if you have a worn RN slide and are intending to try and remove the special throttle needle holder, to re-use it on a new TT type slide - the original fitment of this adaptor is not as straight forward as it looks.  Original slides had ths special needle holder lightly soldered to the throttle slide, and the screw riveted underneath . . . trying to remove that part from an original worn slide will normally damage both the slide and the original slide - we do also sell the throttle needle holder and correct screw seperately - Item No 0962

This is the special needle carrier that were attached to the slide on original Amal RN competition carburettors - allowing the throttle needle to be held remotely from the throttle slide.  CNC machined to the original pattern

This fitting is particular to the Amal RN (Remote Needle) model, and as far as we are aware have been unavailable for many years.  Ours are CNC machined from solid brass billet to the exact dimensions of the original item - including the fine slot for the needle spring clip (Item 0960) and the counterbored screw hole at the top, which allows this clip to be attached to the throttle slide.

We also include the special brass screw that was used to fit these to original slides - which should be flush fitting at the top, so they did not foul the carb top cap.  Email us if you require further information on the the thread and length of this screw - and if fitting this to a new slide - carefully ensure the thread in the slide and screw are the same and a smooth fit - before fully tightening home.

Note: If you own an original Amal RN carburettor, you have probably looked at the slide and wondered how this needle carrier was held to the slide.  It is important to note that it was not retained purely by the screw (which we believe to be a 5/32 x 32tpi BSW thread) - the RN slide also had the needle holder screw hole counterbored underneath, then when the barrel headed screw was fully tightened, the head of the thread was peened into the counterbore so it could not loosen and come away from vibration in use. Added to this, at least two original RN slides I have stripped have also had the brass needle holder soldered to the slide in addition to the screw (but i am not sure if this was done for all slides).

Therefore, if fitting one of these needle holders to a standard Amal TT slide - it is important to bear in mind the original method of attaching, and satisfy yourself that you have fitted the needle holder securely before use.  We also sell complete Amal RN Throttle Slides already (jig) fitted with this special arm, in various slide cutaways - See Item 0961.  These are not cheap - but the arm is already fitted in the same manner as the original items

Note: we can supply high quality slides already fitted with these needle holders in No5 and No6 cutaways if required - Item 0961

Throttle Needle to fit original Amal RN (Remote Needle) Carburettors (i.e T10RN and 10RN9 types). 

Price is Eachl

These throttle needles are similar in appearance to the TT carburettor type - but actually, the correct RN needle is unique to that carburettor type, and are shorter than the TT version (as a footnote to this, amongst my collection of original RN carbs - I had found a number of them had been fitted with the incorrect needle type!).

These needles are high quality UK manufactured with the correct length and taper dimensions, see photograph comparision with an original Amal RN throttle needle. 

If you have an RN carburettor, but are unsure if you have the correct RN needle fitted - email us on sales@racingvincent.co.uk for further details.

Manufacturing Update Dec 2022:  We have both the TT and RN type needles manufadured for us by a UK specialist carburettor parts manufacturer.  However, as with so many other manufacturers, in recent times - getting new small batches made has been difficult.  Such was the case with this latest batch of 'RN' needles, and we were not able to meet the required minimum batch quantity.  Luckily we had just had a larger batch of TT needles completed - and as these are a longer version of the RN needle - we were able to have a number of those needles modified to 'RN' needle dimensions. 

Because of this  - although overall dimensions are the same as original RN needles - these needles have one additional groove at the top that should not be used . . . the top of the needle and the top groove are painted red (to signify this).  The original RN needle had 7 grooves - and these needles have those 7 same grooves in the same position (see accompanyning picture of our needle next to an original Amal RN needle).  If you are setting up your RN carb and experimenting with diffierent with different needle settings (it is normal practice to start with the middle groove position - then move up or down if required) - if you drop the needle to the lowest position of the 7 available  . . . - the red top of the needle should protrude from the top of the special RN throttle needle holder - as shown in the photograph of our needle fitted to the slide.  Please ensure you understand this before ordering - and email us if you require more detail.  

Amal RN Carburettor Background:  The Amal 'Remote Needle' RN carburettor was developed in the late 1930's - as an early attempt to improve the normal Amal competition 'TT type, for outright top speed running.  With this in mind, it was normally fitted to pure competition and TT/GP motorcycles - particularly pre and post war Manx (magnesium crankcase) Norton models - which were normally fitted with the 'Long Neck' RN version. 

As the name implies, the 'Remote Needle' models had their throttle needles moved from the normal position (i.e. TT carb) in the middle of the throttle slide/choke area, to a seperate cavity at the side of the carb body, and the main and pilot jets moved correspondingly, so they were still situated beneath the throttle needle, but provided a more direct route for fuel into the engine (Later GP carb design learnt from this early design, and the needle was moved back into the main choke area - but to one side and the fuel delivery came into that choke area at an angle - a more direct route than the RN design). 

Because of its unique design - the RN carburettor has many parts that are not interchangeable with other models - and because it was only originally fitted to pure competition models - these carbs and the correct RN parts are now generally very difficult to find - or even identify when searching through boxes of old parts!   As well as the RN throttle needle shown here, there was also a RN unique throttle spring, Throttle slide (similar to the TT, but with the addition of a special side bar for holding the throttle needel remotely), different pilot jets (shorter than TT Pilot jets), alloy plug and 'prayer book' spring to block off the throttle needle casting cavity at the top, and RN main throttle body cap and ring.  All these special 'RN' unique parts are available from our Remote Needle Carburettor parts section

Update Nov 2022 - we have now manufactured the special Throttle Needle spring fitted to retain this needle in RN carbs - see Item 1138. 

This is the distinctive lipped circular spring that was used on original Amal Remote Needle (RN) competition carbs to hold the throttle needle to the side bar attached to the throttle slide on Amal RN carbs.  This spring was circular, so that it would fit into the circular shaped Remote Needle part of the carb casting.  Our clips are identical to the original design, and an original spring was used as a pattern.  Price is each - see detail listing for more information

It is worth saying first - that the original spring design as shown here is now extremely rare and difficult to find . . . most original Amal RN carbs I have stripped over the years have this spring missing - and I have seen all kinds of different replacements used to substitute for them - even just lockwire wrapped around the needle and slot. It is also not uncommon to find the later TT/Monoblock throttle needle clip used - by clipping the ends of it - but this often damages the spring and often they can foul the sides of the throttle needle housing - so this is definitely not good practice.

 Our spring whas been manufatured just as the original design using spring steel - using an original Amal RN needle spring as the template - and the dimensions and design are identical - including the slight lip (for which we had special tooling made).  This means the needle can be easily held in the slit of the special RN Needle bar (which sits on the side of Amal RN slides), and the needle position easily changed, just be lifting the slide so this slot sits proud of the carb body.

As you can see - this design was specific to this type of carburettor, so once fitted it would allow the needle position to be quickly amended, but would not foul the sidewall 

Defintitely not as cheap as the 'normal' Amal style of Throttle Needle Clip (our Item 0148) - but hopefully you will appreciate why, as we needed to account for the tooling costs to manufacture this rare and unusual spring

These are needle jets to fit original Amal RN (Remote Needle) competition carburettors.  They are available in 107, 109,113 and 120 (methanol) sizes. Note: these are not the same as TT needle jets (unlike main jets which are interchangeable with TT main jets).  

Price is each

Update Dec 2022: New batch now back in stock

RN Pilot Jets - Background and Manufacture:

Note: just like many parts on the Amal RN (Remote Needle) racing carburettor - the pilot jets are specific to this carburettor, and are unlike the longer pilot jets fitted to Amal TT and other carburettors.  Because of the comparitive rarity of this particular carburettor type, it is not unusual when buying an RN carb (i.e. at an autojumble or online) - to find that the pilot jet is either missing, or might look like a modified 'TT' pilot jet.  (if you are unsure if the pilot jet fitted to your original RN carburettor is correct - you can contact us on sales@racingvincent.co.uk and we will try and help you confirm if it is correct). 

Note:  the Jet Body - that holds the Pilot Jet at the top and the Main Jet at the bottom is the same as the TT carburettor, and takes the same Main jets . . . therefore it is not unheard of for a previous owner to have 'made up' an incomplete RN carburettor, by fitting the whole jet holder assembly from a more common TT carburettor!

The jets we offer here have been CNC manufactured - and have replicated all the key dimensions of the original Amal RN dimensions - as you will see from one of the photographs - as templates we have 'New Old Stock' original (1940's) Amal RN jets - which were still in their original wrappings - for all the 4 sizes originally offered - 107,109,113, 120.  All jets replicate the internal bore dimensions, jet size and height of original jets.  Each are stamped with the jet size on their hex for easy identification.

Fitting Sizes:  It is difficult to be definitive about the correct Pilot Jet size for any particular engine, but if you are unsure what pilot jet would have normally been fitted for your engine, we can give you original information for some models (including makes other than Norton) as a guide - however, it is often prudent to have jets in more than one size, and go through the original Amal tuning instructions for setting up your carb (this is included as part of the Amal competition carb facsimile we offer in the main carb section).

As a rough guide - it was more normal for either 107 or 109 jet sizes to be fitted to 350cc engines and 109 or 113 jets to be more commonly fitted to 500cc engines.  120 jets are also available - which are the largest bore size - these were normally reserved for engines running on alchohol or methanol fuel.

December 2022:  Now back in stock again - all sizes!

Correct type conical throttle spring to fit Amal TT. RN and GP type racing Carburettor's

This type of conical spring were fitted to all the Amal racing carburettors - i.e. TT, RN and GP types.  These are manufactured in the UK and are just as per original. The smaller end is placed on the throttle slide and the wider conical end fits at the top stop the spring moving over to one side.