That's a big sprocket for a "small" bike! Given that (based on experience of a Street Scrambler) the 900s are, if anything, over-geared already. The 1200 Scrambler actually has lower gearing than the 900s.
I went up a tooth on the back to marginally lower my gearing, and my T100 seems much happier. Pickup seems much better and I've noticed little difference at higher speed. You might want to consider an upgrade to a 525 chain and sprockets too. It's a bit heavier but the extra beef should mean less stretch and fewer adjustments.
Beware @Andrew Niven ...... The link says for "air cooled models only" not water cooled, as in the title of your thread!!!
Have a look on Squaredeals they (he, Frank) have a good selection of Triumph Air & Water cooled bits including sprockets. https://www.squaredeals-ltd.co.uk/
