Media Coverage - "Dial-A-Jet" - ATV Illustrated Magazine

Rejet your ATV in seconds, the simple way               By Andrew Smith

      A major nemesis of many ATVers is jetting.  Some hate it simply because they don't understand it, while others hate it because it's so tedious and time-consuming.  For all of you anti-jetting activists, we'd like to introduce you to the Dial-A-Jet from Thunder Products, Inc. out of Richmond, MN.  In a nutshell, what we have here is a product that allows you to adjust your jetting with a couple turns of a screwdriver without having to crack open your carburetor.  Coming from a performance background, I know that jetting is critical to a quad's performance.  Variations in humidity, temperature, altitude, etc., can lose valuable horsepower if you don't continuously tweak your jetting to match what's going on in the air around you.  From the recreational aspect, improper jetting can cut your fuel economy by as much as 20%.  With gas at more than $3 a gallon, it shouldn't take long to realize that fine-tuning your jetting will save you quite a bit of coin in a hurry!
     Developed by Dennis Dean, PhD (doctorate in acoustics), decades age, the original Dial-A-Jet lacked one very important aspect - user-friendliness.  The initial designs were functionally superior to anything on the market, and Dr. Dean was able to set several land-speed records on the Bonneville Salt Flats using this technology.  The problem was that you needed a PhD of your own to be able to use this little device!  It wasn't until Lonn Peterson purchased the rights to the technology that the Dial-A-Jet started to become user-friendly.  Peterson, a long time employee of both Honda and Yamaha and a former dealership owner, knew what ATVers needed and what had to be done to this product in order to make it successful.  While the concept of the product has gone almost unchanged since Dr. Dean's record-breaking runs across the salt flats, the fit and function have changed dramatically to accommodate space constraints and to make the product easier for the general public to use.  The unit is not based on electronics or special pumps, but works on the acoustics of the motor, pressure changes and airflow velocity.  The useful range of the Dial-A-Jet is from just above idle all the way to full throttle, but it only operates it there's a load on the motor.  In other words, if you rev up the motor with the ATV on a stand, the Dial-A-Jet will not function; if you apply resistance at the rear tire, it will begin to work its magic.
     A product of this type has many distinct advantages when it comes to your carbureted ATV.  For the trail-riding and/or recreational enthusiasts the savings at the gas pump are huge, but the advantages can go beyond that.  Last summer, when we took you on a trail ride on the Paiute Trail in Utah one of these little units on each machine would have been manna from heaven!  We started our journey early in the morning, and by lunch time had climbed thousands of feet in elevation; not only were our lungs having a little trouble sucking in the thin air, but our trusty ATVs were gasping also.  If only we'd had a trusty Dial-A-Jet installed, we could have pulled out a screwdriver during one of our scenic stops and, with a couple of quick turns, would have had the same performance and fuel economy as back at the base camp.
     There are also many advantages to this system for the performance-minded enthusiast.  We can't even begin to remember the number of times we've had our quad dialed in perfectly the afternoon before a race, only to show up on race day and find the temperature 20 degrees cooler or hotter than it was the day before, or with drastically higher or lower humidity levels than the previous day.  When this happens there's always a mad scramble to pull apart the carburetor and make all sorts of tweaks and adjustments to get optimal performance out of our machine as quickly as possible.  A potentially dangerous situation arises under conditions like this--or any time that you open up your carburetor--because there's a good chance you may get a small piece of dirt in the carburetor.  It takes only a tiny particle to get sucked into your motor to cause damage or, worse yet, make the carburetor slide stick on you.  The Dial-A-Jet is the remedy for all of these problems.  All adjustments are made externally so you never have to take a chance on exposing your carb to the environment, and adjustment is so simple that it takes minimal time to make the changes--and most of all, it makes jetting easy.
     The Dial-A-Jet claims to be the perfect device to add when you're putting in a new air filter and exhaust system.  The added airflow from these modifications will require you to rejet the carburetor, and Thunder Products says that this is the optimal time to add one on.  We decided to take an alternate route here and try to add a Dial-A-Jet to a very poorly jetted Polaris Scrambler 400 (the jetting on this poor Scrambler wasn't off by just a bit--it wasn't even in the ballpark!).  We had a novice mechanic help with the installation (OK, maybe it was more like we had our novice mechanic do the work while we oversaw what was going on so we could get a second-hand view of the installation).  Our reasoning for this was that the novice mechanic needs to follow the directions, and any unclear or confusing sections of the instructions will become very evident.  What we found is that the Dial-A-Jet comes with a very complete and concise set of instructions that even a trained monkey could most likely follow.   The most difficult part of the installation was probably figuring out how to orient the Dial-A-Jet so we could still access it in a simple manner.  This difficulty has nothing to do with the product but with the design of the Scrambler's airbox and intake system--while the location of the intake boot isn't very user-friendly, it's still easier than trying to get at and change the jets.  When we found the orientation that would work best, we used the supplied tool to poke a hole through the airboot in order to install the Dial-A-Jet.  After installing the main portion of the kit, we needed to put in the fuel feed portion.  This is where we ran into a minor snag.  The Scrambler used a Mikuni carburetor, so we needed to drill and tap the carb's drain plug to install the fuel supply valve.  This portion was a breeze; the snag came when it was time to reinstall the carburetor.  On the Scrambler there's a rubber support block under the carburetor to support it during the inevitable crash or rollover.  Unfortunately, this rubber block sat right where we just drilled and tapped in a new fuel supply fitting.  The quick, simple fix was to carefully drill a clearance hole through the rubber block to route the fuel line while still leaving enough of the block behind to safely support the carburetor.  This wasn't a major setback, just a step that wasn't planned for in the instructions.  After getting the supply lines run and the valve installed in the intake boot, the only step remaining was to install the snorkel kit.  Basically, the snorkel kit is a system that pre-filters the air before it enters the Dial-A-Jet.  We highly recommend this option for any off-road application.
     The last item we added was a TPI (Total Performance Intake) valve, which is a sliding door that allows more or less air into your airbox.  Installed either in the airbox cover or the airbox itself, it enables you to let in the amount of desired air through a foam filter setup.  The design allows you to quickly and conveniently pre-filter the air before it gets to your normal air filter.  The kit comes with a simple-to-use template for laying out the pattern and utilizes six screws to hold the valve into position.

THE TEST
     After installing the Dial-A-Jet, snorkel kit and TPI valve, it was time to see if we could get our coughing Scrambler whipped into top shape.  We went down slightly on our main jet size to help with some of our existing problems and would work with the Dial-A-Jet to work through the rest.  What we found our was amazing.  Previously it would have taken us over 20 minutes to adjust the jetting' now it took less than two!  It was simpler and worked better than anything we had ever worked with before.  In no time we had our Polaris scrambling around the fields with the crisp throttle response it should have had all along, and on days when the temperature and/or humidity changed, we are able to adjust things with simply little time or effort.
     Trying out this little device convinced us that we need one on almost every one of our carbureted toys to get the maximum potential and efficiency out of the motor.  The improved fuel economy alone will more than pay for the minimal cost of the kit (MSRP: Dial-A-Jet, $74.95;Snorkel kit, $9.95; TPI Valve, $19.95).  This item is perfect for sport or trail enthusiasts alike; everyone with a carbureted ATV has a lot to gain by using a Dial-A-Jet!

CONTACT INFORMATION
     For further information contact Thunder Products at 21676 Deep Lake Road, Richmond, MN 56368,  320-597-2700, or visit their website at www.thunderproducts.com.