Triumph had issue with 2005 speed triple plug holes. During washing or rain the coil insulation rubber lets water to the spark plug area and this tends to rust the spark plug holes and plugs. Newer models had better design which fixed this issue. You can order newer model rubber seals for the stick coils and upgrade your older model to the new level.
All too common sight for speed triple owners.
New rubber on the left. Old one still around the stick coil.
Mounted. Old one (left) and new one (right).
The water can also cause running issuws.