Jack,
The TR1 was the XV920R with an XV1000 (981cc) engine.
In the US, Progressive Suspension offers front and rear springs.
Dynojet used to offer a jet kit for the old XV750/920, perhaps their current XV750 or XV1100 kits will work.
K&N offers an airfilter that fits the stock airbox.
Dial-a-jet offers a kit for the XV920.
If you get deeper into it, Megacycle and Webcam make/made cams for the XV750/920. Megacycle also offered valve spring kits, titanium retainers, adjustable cam sprockets, and Venolia pistons, 11:1, 92.25mm or 94mm bore.
Let us know how things go. Good luck,
John