Dial-a-Jet Carburetor kit.
For my back up quad I have a 1999 Big Bear 350.
If any one out there has an older ATV you know how hard it is to get upgrade parts for a 10 year old ATV.
First of all I ordered a pipe for it that didn't fit and when I called the company and told them that their pipe didn't fit my 99 Yamaha Big Bear 350 they told me "yes it does" because their research and development folks say it does. Even though at this point it didn't matter because I was going to send it back anyway, I still had to prove to them that they were wrong.. which wasn't that hard. They had sent me a pipe for the 2000 year 400 engine, which has a different style exhaust. They must have assumed that the 350 and the 400 were identical.
I then began looking for another pipe or mod that would fit that didn't cost an arm and a leg and that would give me a substantial HP or Torque per $ gain.
One of my concerns was that I live in the desert in Las Vegas at about 2000 feet in 110+ degree weather.
Also, a lot of my riding takes place in Utah on the Paiute trails that varies from 7000 to 10,000+ feet and often drops below freezing.
I am constantly changing jets every time I take a trip to Utah and changing jets every time I return.
With a pipe, I would still have to change jets and I probably would have to buy new jets to make up for the freer flowing exhaust that I just paid several hundred dollars for, and how much gain would I really get on the old 350 thumper for that several hundred dollar investment?
How often would I have to worry about re-packing the aftermarket exhaust?
Researching the forums and talking to others with pipes I would get the same old " I don't know how much power I gained but it sure is louder.." comment.
My research led me to the Thunder Products Dial-a-Jet
http://www.thunderproducts.com/dial_a_jet.htm.
The Dial-a-Jet is basically a 75.00 box of plastic tubes, a small adjusting Dial-a-Jet body, and some fittings.
How could this possibly give my old Big Bear more power?
Boy, let me tell you... This thing rocks..
Before I installed the Dial-a-Jet I took the Big Bear out to the desert and to Utah and did some speed testing.
The fastest I could get out of the old Big Bear was 38-40 mph per my GPS.
From a dead stop I don't think it is possible to pull a wheel of the ground while sitting in a normal position, maybe if you stood on the back of the rear rack....maybe.
I then installed the Dial-a-Jet per the instructions using a main jet that was 2 sizes leaner than the factory jetting.
I also ordered and installed the snorkel kit that is a tube and foam filter that re-routes the Dial-a-Jets air intake to where ever you want it to be. On my ATV I ran it up to the highest spot I could up under the front of the gas tank.
The installation took a little over a hour but was relatively simple and the directions were pretty easy to follow.
After I was done the first thing I noticed was that starting the engine needed much less choke than before.
After warming it up I took it out for a test run and I was amazed at the bottom end torque I had available. The Big Bear actually got the front wheels off the ground from a dead start with me sitting in the normal riding position. Not a wheelie but any means but it did make a big difference from a dead stop.
I played with it for a little bit around the yard and then took it out for a top end run.
I was very pleased to see that the Big Bear was now pulling 45 mph on the top end. That's a gain of 5-7 mph on the top end.
I was very pleased with the results but I still needed to take it to altitude to do the final test.
My 1st ride was locally here to Mt Charleston. I have a trial that takes you from about 3000 feet to about 6385 feet. The Dial-a-Jet worked flawlessly.
I then took the Bear up to the Paiute trails in the Yankee Meadow area. Here the elevation goes from about 8000 feet to 10000 feet. Once again the Dial-a-Jet worked perfect. The bike needed less choke to warm up and no jet changes were necessary from the 2000 ft elevation of the Southern Nevada desert. During the run I removed the plug several times to make sure it was burning properly and it was nice and tan for the whole trip.
Last weekend some friends of mine and I went to the desert with my quads and a 08 Rhino.
The Rhino owner wanted to drag race my 700 Grizz and the Big Bear.
So we found a long stretch of flat land and went at it.
I never saw either of them until I stopped and turned around.
The Big Bear with the Dial-a-Jet couldn't get off the line as fast the Rhino but would stay about 10 feet behind it for 50-100 feet and then actually began out accelerating it. The Rhino beat it, but only by a 1/2 Rhino length in the 150ish yard run. Not bad for a 10 year old stock 350 2x4.
I told a friend with a Artic Cat 600 about the Dial-a-Jet and after installng it on his AC he was very impressed with it also.
In my opinion there is no other 100.00 investment that will provide you with the gains that the Dial-a-Jet will get you.
If you have a carbureted ATV I would not hesitate to get a Dial-a-Jet. It is in my opinion the best HP per dollar investment out there.
To understand how the Dial-a-Jet works go to
http://www.thunderproducts.com/dial_a_jet_techpaper.htm
The following is from the Dial-a-Jet tech paper.
"
Three things trigger Dial-A-Jet's fuel signal: 1) engine pressure drop (vacuum or fuel signal); 2) acoustic sound signal which either amplifies or de-amplifies the reversionary pulse waves of the intake tract (we will explain more about the acoustics later); and 3) air flow and velocity. Dial-A-Jet works from just above an idle all the way to full throttle. Dial-A-Jet automatically gives you a perfectly calibrated carburetor that feeds fuel linear to engine load. Feeding fuel linear to engine load means being jetted properly whether you are pulling a heavy engine load like a hard hole shot with good traction or just cruising easily on hard pack at 40mph. Various speeds and engine loads require changes in your fuel curve. Dial-A-Jet automatically monitors your engine's needs then alters your fuel curve to match. A load must be placed on the engine for Dial-A-Jet to function. You can't rev your engine up on the jackstand and watch fuel go up the lines. Without loading the engine, there is no need for extra fuel; therefore, Dial-A-Jet does not deliver fuel. This is normal."
Linear Mode
