Amal t15 tt International

TT carburettor used on a 1955 Manx Norton

The TT (Series 27) was introduced in 1932 as a progression of the Type 27. A needle and needle jet were incorporated to provide additional tuning for road machines and when the carb was used with alcohol as a fuel. Pre-war models were suffixed with the year of manufacture but when production resumed after WW2, all of the TTs had a 9 suffix regardless of year.[34]

As well as the spigot mounting as used by the Type 27, flange fixing was introduced. As the spigot mountings were susceptible to air leaks, flange mounting was seen as an improvement.[34]

Three body sizes were made:

• 25TT - 3/4" and 7/8 bore diameters
• 15TT - 15/16", 1" and 11/16" bore diameters
• 10TT - 1 1/16", 1 3/32", 1 1/8" and 1 5/32" bore diameters[35]

Sales of the 25TT were small and the model was discontinued in 1934. Production of the other two versions continued to 1954.

also take a look at Burlen website. Amalcarb.co.uk downloads and parts 

J

Hi Tomas,   I would try the carb on your 350,  For road use it may be ok.  

Your 15/16" is correct for your 350 Inter. Fit it!

Incidentally...the later Dommies (SS models) had bigger inlet port diameters (designed for racing) than carburettor sizes (intended for road use) and they had sleeve tubes fitted as standard to reduce the step up and maintain gas velocity. But for road use...who knows?  If you prefer tinkering to riding, you could experiment.

Hi Tomas,

   You really need to find a 1+3/32 inch (28mm) 10TT if you want top speed. These cost around GBP 250+, but you could fit a 289 pre-monobloc with the correct 15 degree float chamber with equally good performance at a lower cost. You will also need at least 8.5 to 1 compression ratio, as the Scott is a 2 stroke 600cc twin and has 4 power strokes compared to the Inter's 1.

Tomas; head looks to be iron, due to corrosion marks on some fins.  Tap it with a metal tool; if it  "rings" its iron,  it its a "thud" its alloy. 

Cambox looks to be alloy as the contrast in colour from inside to out shows it quite light.  The   Magalloy unit is a darker grey colour.  The cast number on the  left side of the head/  what is its  full number;  What is your engine number first two digits?

Jon

Surrey Cycles only list the 1 5/32" size TT carb, at nearly £750 without float chamber.  ,(They suggest a separate 'matchbox' type for another £100 or so.

The 1 5/32" was standard on the 500cc Inter.  The 350cc used the one you already have back in the day when Norton sold the Model 40. It's your choice.

Ps..always sold in inch sizes. 25.4mm per inch!

Hi Tomas,

   Your crankcases might be replacement ones as there is not the normal stamping on them. If the number is correct, it is from 1952 and these engines were mostly fitted with aluminium heads and barrels by that time.

Thomas...the "right carb" is the one you have. I think you mean "a different carb"!  If I were putting the bike together, I'd try the right carb (the one you have) first. Norton knew what they were doing. If you find yourself running on full throttle and still hoping for more, you can deal with that later.