Have you adjusted your clutch cable recently? The clutch is on the right side, about halfway back on the engine. A slipping clutch smells like burning electrical insulation. Make sure you don't have the cable cranked down too tight, because Triumph won't warrant your clutch. A new clutch assembly is very expensive.

It is easy to make sure you have enough play in the cable, so it is an easy fix- if you don't keep slipping it, you should be fine.
If that doesn't help, then we can go on to plan B to try to figure it out.