Upgrade Your Bike: Part 2 – Cam Selection

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April 7, 2010 | By: Anthony Todd

In Part I of this series, I told you everything you needed to know about the basics of upgrading your motorcycle’s exhaust system. Today, I’m going to take you through basic considerations when upgrading your bike’s cams.

Cams are one of the top five performance parts that are incorrectly selected for motorcycles. Most people assume the bigger the cam the greater the power. That’s not always the case, as more power will not do you any good if it doesn’t match your riding style. A bad cam choice will result in a substantial decrease in real-world performance.

Riding style in relation to rpm is the key factor when selecting your cam and below are some examples of different riding styles and what rpm range will result in the best real-world performance gains:

  • Street Riders (2000- 6000 rpm): Street Riders typically want a bolt-in cam that will increase performance a step above stock. This will improve day-to-day riding with the ability to have a performance increase during leisure riding or wide-open throttle pulls.
  • Touring Riders (1800-5000 rpm): Touring Riders typically need more power in the cruising range. These riders typically ride two-up with full bags and require additional power to pull inclines, enter/exit highway ramps and pass other drivers.
  • Performance/Racers (2500-Redline): Performance enthusiasts typically want all their power in the top end of the rpm range.  They spend most of their time at wide-open throttle and rarely see the lower rpm range.

To pick out the right cam for your riding style, ask yourself a few questions:

  1. What application am I going to be using this cam for (racing or everyday driving)?
  2. Where do I spend most of my time riding (what rpm range)?
  3. Do I plan any future performance upgrades (displacement increase, gearing changes, etc. that might impact my cam’s performance)?

Once you have answered these questions, you should take a peek at the cam grind charts offered by different manufacturers. Most, if not all of their specifications, are listed in black and white, telling you what the cam will do in relation to your motorcycle’s displacement, target rpm range and the overall performance expectations. You’ll probably be surprised to learn how few cam grinds are available that will work in conjunction with your questions.

Selecting a camshaft can make or break your motorcycles performance. If you are doing the installation yourself, feel free to contact our tech department for a second opinion. If you have an engine builder or mechanic installing your parts, run the cam specifications by that expert for added confirmation.

Now that you’ve picked a cam, but before you actually purchase it, make sure to check the condition of the other valve train components in your motorcycle. Check your lifters and valve springs, and then check your compression.  Complete a leak-down test to determine the condition of the valves and valve seats.

Just like I did in the first part of this series, I’m going to tell you what our in-house tech experts prefer and why. Here in their own words are what Scott Holton and Bud Milza have to say about the camshaft selection:

Scott (who says he prefers performance cams): “When choosing a cam for performance, there are a number of things to look for.  Longer durations and higher lifts generally help in higher rpm applications, but the static compression ratio of your bike has a major influence when things start to boogie. If your bike has high-static compression, a longer overlap time can bleed that excess pressure away. If your bike has lower-static compression, choose a shorter overlap cam with an early inlet valve closing time in order to start building power sooner in the rpm range. As I ride a smaller, lighter bike, my needs are for a higher lift, longer duration, more overlap type cam. Even though I’m the large economy size, my Indian does an excellent job with the EV 5 cam I run.”

Bud (who prefers more of a touring cam): “I ride a Road King that is a little on the heavy side.  After adding an air cleaner and a two-into-one pipe, I still felt the need for more power — especially when riding two-up or loaded down with luggage. Cams with less duration are generally preferred for heavier bikes to get them from idle up to cruising speed.  But since I ride a 103 with a 6-speed, I chose cams with a little more duration to continue delivering power higher up in the power band.  The Andrews 55H cams provide exceptional power from 2000 to 5000 rpms. Whether I’m ripping around on the street or passing between 70-90 mph on the highway, I couldn’t be happier with my cam selection.” 

My next post in this series will cover other bolt-on upgrades to complete a performance project. As always, if you have questions or need assistance picking out the cam to suit your needs, don’t hesitate to chat with a J&P technician via Live Chat. Or call J&P’s technical support staff at 800-397-4844. 

Comments: 2 Comments | Categorized Under: Tech Tips

Comments (2)

[...] everything you need to know about the basics of upgrading your motorcycle’s exhaust system.  In Part 2, we talked about how to select your camshaft, based on your performance needs. In this final post [...]

Andrews A grind in a 86″ Shovel… kick starts every time, idles nice and has just enough “goomph”.

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