Saturday, March 15, 2025

Updated Motorcycle RPM Benchmarks

Pre-mod on the Italica Bulldog 150:

  • Takeoff from a standing start at about 3,500 RPM
  • 35 miles per hour at about 6,000 RPM
  • 45 miles per hour at about 7,500 RPM
  • 55 miles per hour at somewhere between 8,500 and 9,000 RPM
After the variator/clutch spring/belt upgrade:

  • I forgot to look at takeoff RPMs. I may come back and update that measurement later
  • 35 miles per hour, unchanged -- about 6,000 RPM
  • 45 miles per hour, dramatic improvement -- about 6,500 RPM
  • 55 miles per hour, fantastic -- about 7,000 RPM
I managed a top speed of 58 miles per hour on the nice, flat, straight road near my house. That's in line with my previous experience, although I think I have hit 60 miles per hour under perfect conditions before. Anecdotally, I think I've got faster early acceleration as well.

The mechanic told me to expect some changes, probably for the better, after the next 100 miles or so (and cautioned me to take that 100 miles in increments of no more than 25 miles or so). The kevlar belt takes longer to stretch to its final length/tautness than a regular rubber belt. If the changes aren't for the better, I can take it back for a little bit of adjustment tuning at no extra charge.

I'm incredibly happy with the performace gain here. For practical purposes, a 55mph top speed is just fine, and not the engine isn't working nearly as hard to maintain that speed.

Update: A picture of the bike rocking its $7.xx "underglow" lights. They're color and flash adjustable, and I'm using a yellow "breathe" pulse. When I get "real" underglow I expect a different look, but either way a little more visible to the traffic around me at night.