BUYERS GUIDE TO PERFORMANCE PARTS

Buying Performance Parts For Your Bike

If you've ever looked through a parts catalog, then you know that there's literally thousands of brightly colored after-market parts, with snappy names, claiming to give your bike INCREDIBLE POWER INCREASES!  Now if you look at the price tags for these items you’ll understand why the saying goes “you can make your bike as fast as you want to spend.”  Its also important to note that the amount of increased power you can squeeze out of a bike is subject to the “law of diminishing return.”  That is, if it costs $300 to get your first 20% increase in horsepower out of your bike, it will likely cost around $10,000 to get the last 10%.

You’ve likely seen parts referred to as stage 1, 2, or 3.  This is because engines should be modified for performance in stages.  By working systematically through the stages, you’ll ensure that you’re getting the biggest boom for your dollar.

Categories of Performance Parts 

There are basically five systems that you are upgrading to increase your bikes performance.  They are Intake/Fuel, Exhaust, Ignition, valve train, and displacement.

Intake

 

Intake is pretty straightforward; if you get more air into the engine, it can make a bigger explosion.  Fuel is directly connected to this, as you must increase the amount of fuel in proper proportion to the increase in air.  (This is covered extensively in the previous post Carbs 101) (Oh and if your bike is EFI you are going to hell)

Higher performance is here begins with a high flow air filter, and ends with high flow heads.  Don’t get carried away with flash; my advice is to spend wisely and save your money for more performance.

Note* velocity stacks don’t filter the air and are truly meant for racing.  Don’t run velocity stacks unless you love cleaning your carburetor.

Exhaust

For many v-twin owners, the first modification is to swap out those stock exhaust pipes for some stylish drag pipes.  While this will make your bike heard for miles, it does little to nothing to help performance.  As far as performance goes, nothing can beat a good 2into1 exhaust. I know it seems counterintuitive to cram more exhaust into one pipe, but these systems allow the exhaust to work off of each other’s momentum and create a broader power band.  Typically high-end sport bikes will come stock with a great exhaust system, but that doesn’t mean that you can’t spend 2-3k for one or two more ponies.

Ignition

Simply put, a more complete combustion will create more power, and in order to get better combustion you’ll need more electricity at the spark plugs.  Upgrades begin with higher performance plugs and wires. The next step is different depending on the type of ignition your bike uses.  A high performance kit for a CDI unit, for example, will consist of high voltage coils and pickup coil.  Ignition kits are common and affordable.  Just make sure you buy a reputable brand.

Valve Train  

The valve train may use either a pushrod system, or overhead cams.  Either way the goal is the same.  In order to get more power, you need the valves to open wider and stay open longer.  This requires swapping out for high performance cams with more aggressively angled nodes.  Lighter push rods, rocker arms, and valves will help prevent you from floating valves when using these high performance cams.

Displacement

Upgrading an engines displacement seems like one of the most intuitive upgrades.  (If you want more power, get a bigger engine)  This, however, is not always all its cracked up to be.  First off this is one of the most expensive and labor-intensive upgrades you can make.  Second, while upgrading to a larger size engine will make more power, it may not change the power band in the areas you want.

   

So what should you do when?

Here’s a chart of performance stages that applies to most bikes on the road.

 Performance Stages

Hopefully this helps you wade through the sea of performance parts, and start spending your money more effectively.