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TT Special Specifications

Main TT Special Specifications (where different from the T120R)




E3613 12:1 CR pistons

Amal Monobloc 389/95 1-3/16” carbs with 330 main jets

(no special adaptors listed to connect them to the 1-1/16” inlet tracts of the standard 1963 T120 head)

AC magneto ignition with Energy Transfer (ET) coils (fitted under the seat), stator and associated parts, including contact breakers and condensers

17 tooth gearbox sprocket (except for the March 1963 batch of 117 which had 19 teeth ones)

High level exhausts with extension pipes and leg guards

Sump plate

Tachometer (no speedo)

19 x 3.50 front tyre



As 1963 except:


E5727 cylinder head

E5351/E5352 tapered carb adaptors

ET coils re-located under tank

17 tooth gearbox sprocket throughout

H1287 top yoke with pull-back handlebar mounts and steering damper knob

H1717 fork assembly with hydraulic dampers that screwed in to the top nut (available from January 1964 as an option). New forks with external springs were introduced across the “B” range for 1964.

Polished alloy mudguards for JoMo. For TriCor, painted steel, Alaska White with Gold centre stripes and Black coachlines. However, new evidence in the form of a letter* dated 11th December 1963 from Dennis McCormack to East Coast dealers (see Service Bulletins tab) indicates that polished alloy mudguards were available as an optional extra on TriCor TTs with a surcharge of $6.75. I expect most owners would have paid the surcharge for the alloy fenders (they look better and are more appropriate for a race bike than steel ones), and therefore that most of the 202 East Coast TTs built that year would have left the factory with alloy fenders. Restorers - particularly in the UK - tend to work on the assumption that painted steel 'guards on East Coast TTs are correct for 1964. It's not quite as simple as that and I would think it more likely than not with an East Coast '64 model TT that it left the factory with polished alloy fenders.

* Special thanks to Mark Mittlestadt of Recycled Cycles for providing a copy of this letter.



As 1964, except for folding footpegs and underslung TT pipes.

No sump plate as standard, though these were always an option

Painted mudguards introduced for East Coast TTs (alloy front, steel rear) though the first batch (built in August 1964) of 55 retained the alloy ones. [This is claimed by David Gaylin in his "Restoration Guide" (though he gives the number as 50, while 55 from the first batch went to TriCor and if this is true I would expect all of them would have had the alloy 'guards, but I don't think anyone knows for sure). I think it's more likely that, as in 1964, the painted 'guards were the default for TriCor bikes and polished alloy were an option at additional cost.]




As 1965. E5047 exhaust cam (racing E3134) from DU31119, the first TT of the December 1965 batch. This new cam was fitted to all subsequent TR6 and T120R models too, so it was a difference only for a very short period!

Most '66 TTs had polished alloy guards though some East Coast ones reportedly had painted (White with Grenadier Red racing stripe) steel ones. Consensus among restorers is that the alloy 'guards were all razor-edged in 1966, though some US owners of original ones dispute this and I have seen photos of originals which seem to have rolled edge guards. Personally, I believe there were instances of rolled anwest d non-rolled alloy guards in 1966 - but this is a hotly contested matter!

Unipiece black air filter on West Coast models (certainly on early ones, though later 1966 model year ones may have had the individual chrome ones); individual chrome air filters on TriCor models - though again it's likely these were introduced part way through the model year. 



For 1967 the only difference in engine spec was the 11:1 pistons in place of the 9:1 ones on the T120R, which by now was fitted with the bigger carbs and associated head and adaptors as the T120TT

Polished stainless mudguards fitted, in common with the T120R - probably razor-edged, but restorers argue about this.

Different tank paint design, with a lower scallop of white (or gold with white edging for the first 400 up until serial number DU46193) and line visible from the side (the similar design used on the larger tanks in 1964 and 1965 had the line running underneath the tank and was not visible from the side - a common error among restorers, largely resulting from a misleading article available on the internet)

New seat design - no chrome trim, as is common on pattern reproductions

No detail changes between West and East Coast models

Individual chrome air filters



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