[grbrown]

Enlarging on Simon's point, let us take a look at what the gearing on a Dyna actually represents. Fifth gear is direct or 1:1 within the gearbox and Roy's original gearing gives a theoretical 135mph top speed in fifth. Raising the gearing with a 34T sprocket increases this to 143mph. In sixth gear, the new gearing corresponds to no less than 168mph.

By contrast I have reduced the gearing of my Dyna, a 5-speed, from 140mph theoretical top speed, to 118. The result is significantly improved acceleration in top gear and reduced gear changing. It now rides like a Harley should, in my opinion!

All Harleys, for many years now, are seriously over-geared as standard. This is entirely down to reducing engine speed, hence noise output, at the road speeds used for noise testing, to comply with emissions regulations.

While Roy may be pleased with the change to his bike, I am inclined to recommend that any change in gearing should be to reduce it and significantly. I now have a 21T crank sprocket, in place of the original 25T. It is the cheapest way of 'tuning' a standard Harley!

In contrast, to enable the engine to overcome the standard gearing, to the same degree my Dyna does, requires a dramatic increase in torque, something few of us undertake with the modest levels of tuning we normally use (Simon being one of very few exceptions!).