Media Coverage - "Product Evaluation - Dial-A-Jet"
All-Terrain Vehicle Magazine

Dial-in Your Carbs for More Power and Better Economy

     Carburetors are mysteriously imprecise devices.  It's one of the reasons almost every car and truck built today uses electronic fuel injection instead of carbs.  However, in the ATV business, carbs are still the industry standard.  Despite their limitations, they can be made to work with the same kind of crisp power delivery we've grown used to with EFI.
     Here's today's carb lesson.  A Carburetor's sole function is to mix air and fuel together into a fine enough mist or vapor to transfer oxygen into the combustion chamber where ignition takes place.  Get more oxygen mixed with the fuel and you get a bigger bang - that means more power.  As quantities of air increase in relation to the amount of fuel added, the fuel charge becomes leaner and leaner mixtures make better explosions than rich ones.
     There are two problems here.  First, many ATVs are shipped from the factory with their fuel mixtures set deliberately rich.  This is a safety factor the  manufacturers build in to protect your engine from self destructing (overly lean mix fuel mixtures can cause piston seizures as temperatures and elevations change).  Lonn Peterson of Dial-A-jet claims that although some models are spot-on at sea level in California, the average on most stock ATVs is one and even two main-jet sizes too rich.  This is the reason some bikes stumble on take-off or have a flat, burbling sound with slow throttle response up through midrange - they're simply carbureted too rich.  On the other hand, the ATVs factory calibrated for Los Angeles may be too rich in other localities where the altitude is upwards of 1200 feet or more.
     The second problem has to do with the design of carburetors themselves.  CV or butterfly carbs, used on almost all 4-stroke ATVs, have only two circuits: the pilot jet circuit and the main-jet.  At idle and just off idle, the pilot jet circuit is spraying fuel and then as RPM increases, the main-jet takes over.  CV carbs use an accelerator pump to create fuel pressure and the butterfly controls the amount of air being sucked into the carburetor's venturi.  this all sounds very good and the fact is, these carbs are just about bulletproof - except for one thing.  They do only a fair job of atomizing the mixture, especially at low and mid RPM ranges where the velocity of the air being sucked past the butterflies is still slow.  You can actually hear the difference in an engine which is atomizing fuel properly.  On acceleration, good carb mixtures give the engine a crisp rat-tat sound instead of a fat, blubbery note.  Also, the transfer from the pilot circuit to the main-jet can cause a gap in fuel emulsification producing a stumbling effect.
     This is how Dial-A-Jet technology works.  Dial-A-jet is designed to thoroughly atomize the fuel into the tiniest microscopic vapor droplets enabling the maximum amount of oxygen to mix with the gasoline.  With this simple bolt-on device the air-fuel mixture is actually pre-atomized before it enters the carburetor.  The Dial-A-Jet is mounted on the bell mouth of the carb ahead of the butterfly and as RPM increases it pulls fuel from the float bowl where it is inducted into the carburetor's venturi in a pre-atomized state.  This thoroughly atomized fuel charge is much lighter than what is normally coming through the carburetor's jets and so the fuel supply is much more linear or consistent.  this means you'll get crisp, sharp throttle response off idle (pilot jet), right up through the midrange (main-jet) and at peak RPM, too.
     there are more benefits to this technology than just cleaner throttle response.  A side benefit is dealing with poor quality fuel problems.  More and more pump gasoline is suffering from inconsistent added-in elements like benzene, alcohol and even water.  These power restricting materials are constantly "settling in" at the bottom of the carb's float bowl causing varnish and guck.  With a Dial-A-Jet constantly drawing from the bottom and purging the float bowl, there's no chance for these elements to build up and cause problems.  They simply get sucked into the system, emulsified or converted to burnable fuel.
     Another benefit of the Dial-A-Jet is fuel economy.  Because of the finer, leaner fuel mixture it allows, fuel consumption drops by 10 to 20 percent.  Some of this is due to the smaller main-jet sizes allowed with the Dial-A-Jet.
     Other factors are air intake and exhaust pipe modifications.  Dial-A-Jet isn't a product with appeal only to extreme performance riders.  Peterson claims the majority of his Dial-A-jet business comes from ATV owners who have just installed a higher performance pipe or a low restriction air intake.  Many are disappointed with the lack of noticeable performance increase after these expensive mods and have found Dial-A-jet is the perfect cure.  The same holds true with hunters or fishermen who are riding into higher elevations or for those riders who use their ATVs in both the extreme heat of summer and the vicious cold of winter.  With five quick-adjust, manual settings, Dial-A-Jet allows the rider to quickly adjust fuel mixtures under varying ambient conditions.
     Interested?  You can purchase Dial-A-Jet for $74.95 USD and can order it directly in either the United States or Canada.  Contact Dial-A-Jet at 230-597-2700.