After the relative success of the TTR, customers were asking for a faster Series A than the Comet for the road. So more TTR engines were made and fitted into sexed-up Comet cycle parts - thus becoming the TT Comet Special - or TTC for short. Customers could choose what cycle parts they wanted fitted, e.g.: stainless racing tank as per TTR, alloy
composite brakes as per TTR, TT Bramptons, alloy mudguards as per TTR - and so on. The Burman Close Ratio gearbox was also an option. But few of those were made. Unlike the road box, the gears each had 5 'dogs' for slicker changes. All in all, the TTC was an extremely fast and desirable road motorcycle - but the option was dropped after only a handful were made - when the Series A Rapide was announced.
Probably, the most famous TTC was TTC17 the "Cadwell Special". And special to me is TTC20 which is mine - photo attached.
For the road, most TTC engines received a 4X cam, slightly de-tuned from the 5X version. But the TTR slimmed-down flywheels were retained as were the polished crankcase internals and bronze head, etc, etc.
Peter B