Motorcycle CC to HP Conversion Calculation

I see questions regarding how to convert motorcycle engine CCs to HP a lot in motorcycle forums and communities.  It’s kind of a strange request for a few reasons.

First, motorcycle specs are all over the internet.  Simply pick your favorite search engine and plug in: “Year Make Model Specs.”  Unless you are rocking some super obscure ride, you will probably find a few websites that you can cross reference against each other.

I have to assume that the people asking for an online motorcycle CC to HP calculator have already tried Google to no avail.

Then, of course, you could also just take your motorcycle down to the local tuning shop and throw your bike on a dyno.  You aren’t going to get a better or more accurate motorcycle CC to HP conversion than that.

However, again, I have to assume that maybe there isn’t a local shop with a dyno available or you simply want a back-of-the-envelope style conversion calculation without spending any money.

Well, that is completely fair, and I have to admit that the question really got me thinking about a ballpark calculation.  Keep in mind that ballpark is exactly what you are going to get – a range of CC per HP.  Motorcycles come in such a wide variety of shapes, sizes, designs, and uses that the conversion factor can vary kind of widely.

However, there is still a confined range, and that is what I am going to provide here.  Also, please keep in mind that “power” is more than just “horsepower,” but this tend to be people’s go-to metric for power measurements.

In general, a modern motorcycle will produce 1 HP for every 4-20cc.  The range seems kind of wide, but bear in mind that (1) race bikes and dirt bikes reside at the bottom of the range, (2) factory sport bikes and dual sports sit in the middle at about 10-12 CC/HP, (3) factory Harley’s (including mine) and cruisers can go as high as 19 CC/HP – but they, of course, have the CCs to make it happen ?

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Also, forgive any typos or grammatical errors a I wrote this blog post from my phone.

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  1. Nelson March 7, 2018
    • Christopher Pumo March 7, 2018
  2. Andrew July 31, 2018
    • Christopher Pumo August 5, 2018
  3. Dan Levengood January 12, 2020