High quality throttle slide to fit original Amal 10RN and T10RN Carburetter - whicih includes the distinctive remote needle holder attachment, attached as per the original manufacturing process - see detail listing for more information. As originally fitted to most pre-Featherbed M30/40 and Manx models, as well as many other competition bikes. Price is Each.
Update October 2021: These slides are now in the final stage of manufacture and should be available early November 2021 - email to reserve - email@example.com.
They are available in both No5 and No7 slide cutaways - the most common cutaway types as used on Manx competition models fitted with original Amal RN carbs..
Stocks of this type of slide will be limited, so if you wish to reserve one then email us on our normal firstname.lastname@example.org, stating which cutaway or model you wish to fit it to. We will not know final pricing until fully manufactured, but we expect the slides and adaptor to be fully ground and nickel plated as per the originals and the adaptor to be fixed to the slide as per originals.
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 will normally damage botht the slide and the original slide - we do also sell the throttle needle holder seperately - Item No 0962