Dyno Run

Dyno ResultYesterday a local bike garage here in Canberra had a promotional dyno day.  For $30 you had your bike run up on the dyno to see how much horsepower it’s putting out and also to get an air fuel ratio (AFR) reading.  After the rejetting work I did on my Road Star’s 42mm Flatslide at Christmas I was very keen to see how the bike was handling.  I’m reasonably happy with the attached result, it’s showing the bike isn’t overly rich (although could be a tad better in the midrange) and at 71hp it was putting out more power than I thought it would. 

So why is this important?  Well if I was running too rich it would really add up during the Around Australia trip because 14,000 kilometres is a lot of fuel to run through the bike.  Before Christmas the bike felt like it was running fine but I was getting only 13 kilometres to the litre (30mpg) – based on that I was looking at around $1,507 in fuel allowing for a trip average of $1.40 per litre @ 1076 litres.  After rejetting at Christmas I have since gotten 19 kilometres to the litre (45mpg) – that works out to be around $1,031 @ 736litres.  A saving of almost $500!

The attached dyno run suggests I could potentially gain just a bit better fuel economy still, so in the coming months I’ll put some thoughts into tweaking the carb further.  For the Road Star readers my 71hp was obtained with the following mods:

  • 1602cc engine
  • Kuryakyn Hypercharger
  • 42mm Flatslide carb
  • Speedstar ported Manifold
  • Dyna 3000 ignition
  • Bub’s Jug Huggers exhaust

Oh and for bragging rights I might just mention I did 1hp better than a Harley Davidson Rocker, but was pipped at less than .5hp by a Anniversary Edition Harley Davidson Road King.