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As a western hill-banger, I have always fought with jetting. When thetemperatures plunged to sub-zero, I dreaded changing jets and getting thatfrigid fuel on my fingers. I praised Cat's fuel-injection, and still do.Ski-Doo's HAC, Polaris' ACCS and Yamaha's SmartCarb also sold me over. But then I checked out the Dial-A-Jet. I talked with performance shop experts,dealers and the inventor himself, Lonn Peterson. Dial-A-Jet passed the snooptest. Good product.
Dial-A-Jet works on the principle of pre-atomizing or emulsifying theair-fuel mixture before the fuel passes through the carb horn and into thecrankcase. As fuel and air flow, according to Mr. Mikuni, they begin toatomize at the carb intake and finish in a complete atomized state (theterm "complete" is used loosely here) in the combustion chamber.One of the Dial-A-Jet's attributes is its ability to enhance atomization,making it more efficient and complete. Dial-A-Jet pre-atomizes the fuel to 10 percent of its original weight.
Additionally, Dial-A-Jet supplies fuel only when needed, namely, when under load. When you're cruising along a nice hardpack trail, for example,Dial-A-Jet will supply the necessary fuel for the motor load. When you decideto rip off the trail and dive into deep powder, the Dial-A-Jet will sensethe increased load and respond accordingly, so you won't have to changethrottle positions for increased fuel and air.
Dial-A-Jet virtually eliminates lean burn-downs. Many of us know richoxygen bangs out the horsepower. With the snowmobile leaned down three sizes,the total amount of fuel delivered will be fatter than when the main jetis operating independently.
Dial-A-Jet provides immediate throttle response. For example, we haveall experienced bog or hesitation when the carbs are slashed open. Someattribute this to the big gulp of fuel dumped in the engine, which causesthe motor to choke on its dosage. Wrong. When the carb slides are slammedopen, air screams into the crankcase in amounts greater than the atomizedfuel. The Dial-A-Jet will emulsify fuel during a quick throttle rip, allowingfuel to be pulled in, in proper amounts.
Dial-A-Jet also purges the carbs of water. Because Dial-A-Jet pulls fuelfrom the float bowl's bottom end, it also draws water and alcohol through,reducing the droplet size by a huge factor. This will allow the water topass through the brass fuel circuits, and be burned (as efficiently as watercan be burned). Also, note that alcohol fuels and fuel dryers have an additionaloxygen molecule that causes engines to burn leaner. Dial-A-Jet will removethe fear of lean burn-down; there's no need to run a richer jet when pumpingoxygenated fuels through the transfer ports.
Tuning for varying temperatures and altitudes can be nerve-racking. Thehigher the snowmobile travels, the thinner the air; then add more fuel inthe crankcase and wet plugs and we have a sick snowmobile. With Dial-A-Jet,it is dial and play. The higher you go, the leaner you can push the mixture.
How to install Dial-A-Jet:
1. Remove the airbox.
2. Hold the Dial-A-Jet on the carb horn either at the 2 o'clockor 11 o'clock position and place a tap through the Dial-A-Jet mounting hole.Tap a drill mark.
3. Remove choke and throttle cables.
4. Remove carbs.
5. Remove float bowl.
6. Drill a hole through the float bowl fuel line boss, and thentap out. Mount the fuel line nipple to the float bowl.
7. On the carb horn, drill a hole through the previously mademark (step two) and then tap.
8. Mount the Dial-A-Jet on the carb horn and fit snugly. To achievea secure fit, compress the Dial-A-Jet unit firmly with your thumb and fingerswhile tightening the mounting screw. Do not over tighten, as you could stripthe threads.
9. Install main jets, three sizes smaller.
10. Add the fuel vacuum line to the float bowl nipple and to theDial-A-Jet nipple.
11. Install the air intake line with the snorkel kit to the Dial-A-Jet.
12. Drop the main jet needle two notches.
13. Reinstall carburetors.
14. Reinstall air box and choke and throttle cables.
15. Thread the air intake lines through the handlebars (dependingon brand and model) for outside air suction.
16. Add the snorkel kit filters.
Dial-A-Jet has great potential. How many times have you cursed your jettingwoes and bottom-end bog on a quick throttle rip? How many times have youcompensated throttle response by adding heavier weights, stiffer drive springsand a shallow helix? Additionally, elevation problems can be virtually eliminatedwith Dial-A-Jet.