Colby,
I also have a 99 and yesterday completed valve adjustment. My engine has 17,500 kms. A little earlier than the 20,000 km recommended - 12000miles ) but based on what I had read on this site about triumph valve clearances tightening up, felt like it was a good idea. As it turned it was!
I had to adjust 8 out of the 12 valves (2 were good, 2 at min) Clearances on many of the valves were as low as .002in (intakes) and at .005 (exhaust). I actually ended up adjusting 9 including the 2 at min.
Just came back from test ride and while it might be my imagination the engine is smoother and slightly quieter at idle and much smoother throughout the entire range.
If you have never had the valves adjusted and you have 20,000 miles, I would definitely recommend you get to it. It is not easy for someone who has never done this before, but possible for someone with some mechanical skills.
Also, I was very lucky, the very nice Honda dealer llent me his entire stock of 25mm valve shims, which I took home with me and I just exchanged the ones I did not use. I was only one short, and another bike shop just gave it to me (without exchange).
Anyways good luck, and let me know if I can help answer any of your questions.
PS: I created an excel spreadsheet which calculates the shims min and max range for you. (on holidays) and as for the tool I reverse engineered my own using some drawings of the original tool. I used some off the shelf metal hardware (90 Degree bracket and a piece of metal. I`d be happy to send a picture of the tool and the excel file to you. I am not sure if I can download them onto this site.
CM
