If you're planning to do practically any work at all on a classic Triumph motorcycle, you'll need a special set of wrenches. Not Whitworth, as commonly thought, but British Standard (BS) wrenches. A few common jobs, like adjusting primary chain tension and the clutch pressure plates require specialized tools which are simple and inexpensive.
Some specialized tools can be easily fabricated even in a very basic shop: the extraordinarily useful clutch-locking tool is an excellent example.
Other specialized tools can be acquired as the needs arise. Still more tools can be acquired while contemplating future work. Aren't tools wonderful?
Using the correct special tool makes a job easier, less frustrating, and avoids damaging the precious motorbike. Or yourself. (ouch!) Take it from someone who's disassembled and re-assembled the Bonnie's front forks with and without the specialized tools.
Note that if the crankcase will be split and the crankshaft removed, a few other tools are required.Comprehensive Triumph 650 Special Tool List