By Matt Celender, VJMC Display Ad Director / firstname.lastname@example.org
In another publication last year, I saw a carburetor modification on a featured bike called a “Dial-A-Jet.” The article didn’t really elaborate on what I t was or how it worked specifically, but I was fascinated at this unconventional way of getting extra performance out of a stock carburetor.
After speaking to Lonn, the engineer and owner of Thunder Products (maker of the Dial-A-Jet), I learned a little more about the operation of this carburetor modification, in addition to an airflow modification called the “Torque Wing.”
Thunder Products provided me with a Torque Wing and A Dial-A-Jet kit to try for myself on my 1986 Kawasaki KX125. The reason I chose this small-bore, single-cylinder bike to test it on is because working with a smaller amount of horsepower, I figured I would see a bigger improvement, if in fact, there was any.
First, I pulled the carburetor off and cut the intake side in a “cross” pattern and installed the Torque Wing – a very easy installation and a modification that speeds up the air flow and atomizes the fuel faster and more completely.
Then as per the instructions for the Dial-A-Jet, I put in a main jet that was three sizes smaller than stock. The bike came with a 340 main jet, and I went down to a 310.
The idea is that the bikes from the factory come with too rich of a main jet so the fuel will be available when needed. The only problem with this theory is that the fuel is there even when it is not needed, and that is where the Dial-A-Jet comes in.
Running a leaner main jet keeps the bike from getting too much fuel not needed as the Dial-A-Jet only provides extra fuel “on demand,” allowing the bike to run leaner, crisper, and cleaner throughout the entire range.
I couldn’t wait to try this system out once I had installed it. Installation was fairly simple, although I must confess that I put the Dial-A-Jet on the right side of the carburetor, not realizing that the shock was in the way of the adjustment, and so I had to move it to the left side of the carburetor where I had full access to it.
The (seat of the pants) test results were very impressive. Normally to accelerate quickly on a small bore (125cc) bike you need to fan the clutch coming out of a turn, or any time sharp acceleration was expected, in order to get the RPMs up. With the Torque Wing and the Dial-A-Jet adjusted properly, I could simply snap the throttle open, and the engine responded instantly, without having to slip the clutch.
The snorkel mounts right on top of the Dial-A-Jet in order to keep dirt out and can easily be removed to make adjustments as needed.
Lonn Peterson, owner of Thunder Products, has worked in the recreational vehicle/powersports business since 1965 and has worked in the research and development departments in both Honda and Yamaha factories. He is always glad to explain how his products work and will answer any questions on installation and operation of his performance components.
I’m glad I had the opportunity to spend some time talking to Lonn and to try some of his products. He has even more mods than just the ones I’ve tested, and I look forward to getting an opportunity to use them in the future as well!