Motorcycle Exhaust Pipes

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Motorcycle Exhaust Pipes & Dyno Tuning - What You Need to Know

Are You Being Duped?

  Did you know that spending money to have your motorcycle's engine control computer flashed to accept a stage 1 exhaust pipe and a high-flow air cleaner installed is a total waste of money?  It is true, for most all modern bikes made today with a 4-wire oxygen sensor.  

  Did you know you are wasting your money to have your bike put on a chassis dyno?  Again, this is true for all modern motorcycles due to new technology of the aftermarket fuel processors. 


  You still do not need a dyno tune-up!  Just buy a Cobra Fi2000 PwrPro fuel manager, plug it in and go.  It self-adjusts and you can take this device to another similar bike for it is not "married" to the bike like other products.  Even if you later install new cams and bored out pistons the device still automatically adjusts making dyno runs obsolete!  Yes, they work on Harley-Davidson's too and it's all plug and play installation.  No need for a computer or download maps, etc.  Yes, read this paragraph one more time!  The new closed loop fuel processors like the Cobra Fi2000 PwrPro require no dyno tuning because it is a dyno tuner constantly tuning your engine.

  If you have that 4-wire 02 sensor on your motorcycle tell the dealer's salesman you don't want their expensive dyno tuning and their flashing of the computer memory to tune the engine to the new exhaust pipe and air filter.  Because it is not needed.  A salesman, due to his ignorance and loyalty to his employer will argue with you about this, but he only wants you to spend money.  He may even tell you it will void the warrantee if you don't dyno tune the bike, but if you do pay the dealer to dyno tune the bike you have voided your warranty and violated the EPA law too boot.  So don't let the dealer hoodwink you to part with your money.

  But there is a procedure you must follow for this to work.  Fortunately it is easy to do.

1.  First install the new exhaust pipes on the motorcycle, but do not install the new high-flow air filter element yet.  Take the bike out for a ride.  A couple miles is fine.  This allows the engine computer to recompute the bike's fuel setting based on the new high-flowing exhaust pipe installed.

2.  Now install the high-flowing air filter element and ride the bike to your delight.  The engine computer will now recognize the new air filter and make the corrections required.  Some bikes won't adjust far enough for the new non-restrictive air filter element and the engine will run rough with hesitations.  Believe it or not, just leave your aftermarket pipes on the bike and install a stock air cleaner.  Yes, it is a tad more restrictive, but you will be surprised at just how little restrictive it is.  You will not even feel any power loss in most every case.   For best results buy an exhaust that has finely tunable baffles like the Supertrapp brand.  You can tune for nice sound, more power and still retain great fuel mileage all without a dyno tune and fuel remapping.  Imagine that!  A dyno tune never give great fuel mileage, they tune for power gain and that means poor fuel economy.  What is sad is the power gain is small, maybe only 5 horsepower, maybe even less power than a Supertrapp exhaust pipe.

The only problem is this:  The stock motorcycle has a lean burn fuel mixture prior to making these changes programmed into the engine computer to meet EPA laws.  This lean mixture will still exist even after this procedure is performed.  It is no big thing and you will not likely notice any power loss or gain even if you do enrich the fuel mixture a bit more using a flash or other fuel management device such as a Power Commander. 

  Dyno tuning can cheat you into believing you are getting a lot of horsepower and many dealers do bend the rules to create inaccurate positive dyno results.  How?  By simply doing a first run baseline with the engine cold on the dyno.  This always results in a drop of 3 to 8 horsepower loss!  Then they install your new higher flowing exhaust pipes and air cleaner element then run the engine when hot on the dyno and amazingly you pick up 3 to 8 horsepower or more over stock, but nothing much has changed! 

  "If you paid to have your 02 sensor bike dyno tuned you wasted your money!"

   They dyno is actually lying to you showing you its higher horsepower reading on the paper print out graph.  Maybe as high as a 15 horsepower gain, but in reality you only gained about three to five horsepower.  Maybe eight if you are lucky!  Insist that you be present at the dyno tuning and they baseline the engine when hot first before making any modifications to the engine.  This will prevent you from being cheated. 

  But remember, if you are only performing a simple stage 1 modification and your bike has an 02 sensor in the exhaust, you are already being cheated paying for flash download of your engine computer, and a dyno run or dyno tune up.  Tell your friends about this rip off taking place by many dealers not being honest with their customers.  Too many dealers are busy selling dyno tuning when it is not even necessary with the new motorcycle engines manufactured today.

  Another thing to consider.  Dyno tuning is normally only for racing applications and heavy engine modifications such as stroker crankshafts, big bore cylinders, hot cams, blower or turbo charging, etc.  Today you can buy self-learning engine control computers that once installed will begin to learn as you drive and make the fuel/air adjustments as required for you motorcycle.  You don't need to put your bike on a dyno.  It is a waste of money.

"The dynometer is a clever tool to steal your money." -

  Remember, any horsepower gain under 5 horsepower you won't notice.  Even ten horsepower gain will be a bit more noticeable, but not enough to require a dyno tune up.

    Motorcycles have been around for a very long time and shops never had dynos like they do today.  Why?  It has become a craze by uneducated riders and sold to the gullible for high profits.

  My advice?  Buy the pipes and the air filter element on the Internet where you will save a bundle of cash and install them yourself.  You don't need a dealer to do this!  See "Pipes You Should Buy" below.


  A lot of bikers are being ripped off by repair shops charging money for dynometer runs.  Don't be fooled.  Most riders do not need any dynometer measurements or adjustments.  Did you know that by changing the air pressure in the bike's tire can raise or lower they dyno horsepower output?  Also, just by tightening or loosening the bike to the dyno will do the same?  How much change?  Ten percent differences that's what.  So that increase in power you are getting on your dyno print out may be fabricated figures to make you believe you gained power when you gained nothing at all.  This means that most bikers who just add aftermarket exhaust pipes and air filter element are being sent to the dyno and given strange print outs designed to deceive the customer.  Save your money.  Keep your bike off they dynometer or pay for the privilege by paying for nothing.  The Harley-Davidson rider is the most gullible and are being robbed and they don't even realize it.

Valuable Link: reveals lots of great advice on Harley-Davidson EFI and engine sensors.


  Many a poor rider has had their bike dyno tuned only to later discover the bike runs rough, makes noise and something is broken.  The dyno is destructive to the engine and drive train due to the extreme loads put on the system.  The are dangerous and most riders do not realize it.  If you do some research about dyno tuning you will discover disaster stories of broken drive belts, snapped primary chains, valves swallowed, crankshafts and transmissions blown.  You need to be fully aware that a dyno will simulate a severe series of drag racing with "abnormal" loadings to the entire bike including the frame which can be stressed to crack welds, burned clutches, broken compensators, etc.  Also, tire manufactures warn you not to subject their tires to the dyno as it can break the internal cords of the tire due to these "abnormal" torque loads on the tires.  Keep your bike off the dyno.  If you do and something breaks, read the fine print as you are responsible, not the dyno, even though the dyno broke your engine/transmission.  And if your bike survives the dyno?  It didn't survive at all, internal engine and transmission parts have already been ruined, bent, distorted, stressed, overheated and now are ready to fail at any time somewhere down the road at a later date.  Now you know why dealers and repair shops love dyno tuning, it's good for business!

  Unless you are professionally racing, you should stay clear of dyno tuning - James Russell 

Install Tires On Motorcycle book

"Learn to Install New Tires on Your Motorcycle and Fix Flat Tires"  click to learn more.  Even Harley-Davidson Tires Too... stop paying, do it yourself... it's easy.  


  A lot riders have chosen the wrong pipes to install on their bike.  Most are "guided" by the dealer who is out to take $1,000 out of their pocket.  Today, you can do it yourself.  Just buy a set of Supertrapp pipes, put them on and you have power and performance without having to retune the fuel mixture.  You save $500.  Plus, the sound volume and tone is "adjustable" with Supertrapp pipes.  Or, you can buy another brand (Don't buy Vance & Hines pipes) and purchase the newer fuel management modules that "self-tune" the fuel mixture. 


  If you paid to have your 02 sensor bike dyno tuned you may have wasted your money!

Note: every motorcycle is different and your bike may need additional fine "tuning" with a fuel management system installed (Harley's need it if they have a two-wire O2 sensor).  If you have a 4 wire O2 sensor system it will adjust itself.  Racing bikes must have fuel management module installed or flash downloaded to the Engine Control Computer.  Heavily bored out engines with cams also need advanced tuning, but a dyno is still not needed.  Today, the engine computer is flashed to accept proven parameters already finely tuned to the engine modifications you have made.  The more you read and study about dynometers the more you will realize they are just a money making machine for the repair shop.  Even motorcycle magazines are misleading millions of riders by recommending dyno runs on reader's bikes.  It is a scam that needs to be exposed for what it is... a clever tool to steal your money.  See the new product below... 


Cobra has finally given the rider a big money-saving product that is not "married" to the bike.  It means it will handle automatically every set up you do to your bike, pipes, big pistons, cams, stroker crank, etc.  No more dyno pulls.  You can remove the product when you sell the bike too, unlike many products that marry the product to just one bike.  The Fi-2000 PowrPro is the product to check out.  It is plug and play.  No downloading computer maps, it adjusts itself.  Yes, you can do it yourself.  This is the wave of the future so you will see more plug-and-play devices  

Why You Should Buy a Victory Motorcycle read this article.

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