3T Triumphs are not common. There are several reasons for this, none of them complimentary to the 3T. Being the bottom of the range and the smallest capacity Triumph of the time they were thrashed unmercifully as everyone expected the same performance as the bigger bikes. As the bike was only ever intended to be a modest tourer the engine didn’t cope well. Then, being the smallest and lightest in the range, the 3T frame was used for the Trophy competition models and every man and his dog made replica Trophies out of any 3T they could get their hands on. If you were lucky you found one with a dead engine and unhappy owner and got it cheap.
Most 3T’s led a short and unhappy life then were either Trophyised or dumped.
The story is different today. People know what they are and treat them gently. They are interesting to Triumph nutters because of the low survival rate. At least they are faster than a Tiger Cub. All in all, a pleasant bike to take on a run as long as you don’t kid yourself you will be the leader of the pack or weigh 18 stone before you put your clobber on.