Auto Adjusting The Timing

There are two means of auto-adjusting the timing on a standard distributor:
1/ Vacuum. This only operates at low throttle openings, and is to improve low speed manoevering, in traffic for instance. You have disconnected yours - fine!
Excuse asking the simple Qs, but have you blocked up the connection to the inlet manifold ?

2/Centrifugal. There is a "moving plate" that carries the contact breaker and the condensor. As said plate sits still while the distributor shaft rotates, its name may be obscure, but it is moved by the vacuum mechanism. Under that is a mechanism of weights that spin with the distributor shaft and move the top of the distributor shaft, with the C/b cam and the rotor arm, in relation to the lower part. This setup advances the timing with the revs, to an extent and a limit governed by the strength of some little springs in the mechanism and the shape of the weights.

It is not unusual for the centrifugal mechanism to seize up, due to wear or dirt, and I suspect this is true for you. The moving plate can be removed for access to the centrifugal bits, so try cleaning it up. Electronic ignition, unless of the mapped, MegaJolt type that uses a different method of sensing engine speed, will not help this problem. If the distributor is badly worn, then a replacement is your best bet.

Here's a diagram of various Triumph centrifugal advance curves:

flickr:2101043240

John on Total Triumph Net

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