Dial-A-Jet (DAJ) Installation

By Tony Anzalone - GoldKnight67 (on the V-Star Forum)

2002V-Star 1100 Custom

Standard Disclaimer:

 I take no responsibility for damage caused to your engine, if you try this project. Tough this is a easy project, anytime you work on fuel systems or modify carburetors you could cause engine damage or fire from loose fuel lines. If you have any doubts about your abilities, consider a competent tech do it for you.

The HP Battle:

First of all, engine designers create high horsepower engines on the drawing board and then they de-tune them by lowering compression, leaning jets, limiting intake and exhaust flow, just to then meet EPA standards. We the consumer, riding the last affordable Hot Rods, (Motorcycles), then spend all out time and money trying to get every bit of performance back.

Generally it is the Exhaust, Intake and Jetting, that get us close to optimal with out buying internal parts, (cams, heads, pistons, etc.). The exhaust and Intake as a rule are easy swap outs for those with some ability, but jetting is another thing, and it is almost an art form.

I have spent many of my youthful hours raising needles, changing jets, increasing and decreasing the length of velocity stacks or exhaust pipes lengths to get the perfect power curve for a certain RPM range. A race engine is tuned to a narrow RPM band at the peak of Torque or HP. Then matched to a transmission that will keep the engine up in the power band as you race, but it is always a compromise. A race-tuned engine is not a joy to drive around town or the open road.

So let us get back to the real world. If I can get a good performance gain with a new product, that offers easier to apply technology for a slight compromise, then I am intrigued. I also wanted to do the performance add on's without totally disassembling my new motorcycle. That is what has led me to the DAJ.

If you need to know how it works:

The DAJ, (Dial-A-Jet), product will only richen a lean engine. If your running rich now you will have to detune or go back to factory specs. "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; and 3) air flow and velocity". See Tech Article for more complete info. Dial-A=Jet is now produced and distributed by Thunder Products.


After discussing my particular needs, (Baron nasty boy slip ons w/ no baffles, and Hy-Flow Intake), with Lonn Peterson at Thunder Products. I ordered the DJ-107A Kit for my Yamaha V-Star 1100 Custom. Just for the record Dail-A-Jet is a independently owned company for the automotive industries, but Thunder Products purchased the water craft, skimobile and motorcycle part of the Dial-A-Jet Company.

The kit appears really simple:

As you can see in the pictures below. 2 DAJ units, fuel line, mounting straps, screws, 2 float feed fittings to replace the float drain screws, and a cutting tool.

Click on image to see larger more detailed picture

Kit & Snorkels   Kit DAJ Unit

1- Find the location:

The kit came complete with tools for mounting in to the intake tube. Try to find an accessible spot on the intake tube, (if possible), just before and close to the carburetor mouth. Accessibilty will vary according to the type of aircleaner you are using. I will be using the Hy-Flow modified stock aircleaner. They can be mounted pretty librally vertical, horizontal, 45 degrees, etc., just be as close to the carb face as you can get.

With the Stock air cleaner I did have a small window to reach the intake tube on the right side, (but if you are using another aftermarket air cleaner you nay not have a accessible spot, so you will have to remove the aircleaner to adjust the DAJ). The left side was very accessible.

Right  Side   Left Side

2- Preperation:

Shut off fuel valve, remove carburetor chrome cover on left side and on the aircleaner on the right side. I was able to remove the air cleaner with the help of a right angle Philips. If you do not have one you will have to remove the gas tank.

90 Degree Philips

2- Fuel Feed Brass Fitting:

The Rear cylinder left carburetor drain is easy to get to, but the Front right side carburetor drain faces the left side and you will need a long small flat screwdriver to reach it from the left side. I stuffed a lot of rags under my carbs to absorb the float bowl fuel drippings. Remove float bowl drain screw and install fuel feed fittings. Tighten with 1/4 inch wrench.


4- Disassemble the Dial-A-Jet per instructions: Remove the fuel delivery brass tube on the Dial-A-Jet.

5- Screw the mounting strap to the Dial-A-Jet.


DAJ Brass Feed Tube Removed                                       Strap Assembly Mounted  

6- Mount the unit on the boot as instructions: Pull the provided strap around the intake tube and position as close as possible to the carburetor. Then pull strap tight to secure.

7- Cut a hole in the intake tube: Insert the Dial-A-Jet supplied cutting tool, through the unit . Then you push and twist till it cuts through the tube. After cutting you should have a plug in the end of the cutter from the tube you just cut. Clean out the tool with a pin and start the second DAJ cut. If you do not see the plug in the end of the cutting tool, I would pull off the intake tube to make sure it is not in there. You don't need to feed your engine any plastic scraps.

Tool fits inside the DAJ in place of the brass feed tube        

8- Connect the fuel line supplied: Connect the fuel line from the Dial-A-Jet, up over the carburetor down to the float feed fitting, if you can? I could not route it as per the instructions, but I did route it up high enough and back down to the DAJ so the line feeding the DAJ will hold fuel and compensate for any siphon effect of deceleration. I also installed the optional braided sleeve over the fuel lines.


9 - Set the DAJ settings:

Because I have a modified stock air cleaner and no baffles within the Baron's Nasty Boy exhausts, Lonn suggested I increase stock DAJ setting, to the right 1 setting  richer, (factory set in the center or the middle of the 5 richness settings).

10- Pilot Mixture Screw and Factory PMS EPA Plug:

The DAJ affects all crcuits except idle to quarter throttle. So the PMS or Pilot mixture screw should be adjusted. But the problem is that there is a factory plug covering this screw.

Removing the idle mixture factory EPA plug that hides the mixture adjusting screw. I asked around on the Star forum if anyone has removed this plug with out removing the carburetors, and was told it was impossible. That I needed to pull the carburetors, find the plug with a tiny hole, then drill it out so as to put a screw into the plug and yank it out. And by the way, make sure I did not allow the drill bit to hit the screw behind it.

Hmmm, (thinking), I hate the thought of having to pull the carburetors off the engine after doing all this work with the bike almost 99% together. So I tried various hand made tools, even a dental tool trying to get into that tight spot to insert it into that tiny hole, but no real progress. Ok time for a little prayer for wisdom & guidance, because I can do all things through Christ who strengthens me.

Ahhhh ...The right tool for the job, yeah, my dremel tool, with flexible extension and tiny engraving ball. Yes, it was a little tedious but that did it, and considering the options of tearing the carburetors off, I am glad I persevered. So, now what do you say, all ye of little Faith. In truth I must say it was the hardest part of this project.


Now adjust the PMS screw according to the instructions. Where to find a screwdriver to fit in there, hmmmm, (thinking)? Mine were factory set at 2 turns out, so I added one and a half turns. That is 3.5 turns open from closed position, as a starting point. After testing, I dropped to 3 full turns out for the Barrons without the Baffles. When I  added the Racing Baffles and  re-set the PMS to 2&3/4 turns out.

Other than the pilot settings, I am using all stock jets and factory needle settings on my carburetors. I will now install the Hy-Flow air intake, modified K&N filter and I am ready to test. See Hy-Flow Article.

***4 Months later: I Installed "Hard Krome Double D's 2.75" Big Staights" full exhaust system and found 3 &1/2 turns out as best with adjustable racing baffle and 3 turns with the HK baffles.


The Evil Plug Location                      Dremel Tool Flexible Shaft                     Removed Plugs      



Turn on the fuel at the tank, turn your key on and let the fuel pump build pressure as the float bowls fill up and check for leaks. Install your air cleaner and follow the instructions and make adjustments accordingly. Basically, it is the same as regular jet testing, except the plugs will be a lighter color since it is a demand system. Even with a normal jet setup it is always "seat of the pants" feel for testing unless you have a dyno to tune on. It is not require but, if you have a carburetor synchronizer tool, this would be my final adjustment.


Left side DAJ is just under easily removed cover               Right side  DAJ is fully accessible above the air cleaner

Last: I also got the "Snorkel Kit", remote filters that tuck away in a protective area to keep clean air feeding in to the DAJ. So now that my settings are finished, I will install them over the DAJ units.

That is it, Done!

Materials Cost: DAJKit  # DJ-107A $103.50, add $19.90 for 2 Snorkels, and add $4.00 for braided protective sleeves.

Totals to $127.40

3 hours labor.

Initial Road Testing:

The first test was smooth as glass with the increased breathing from the Hy-Flow and DAJ jetting. The throttle has a nice chrisp feel to it and the change was most dramatic as I got in to the mid RPM's. Using the same initial install settings, there is a smooth even flow of power with no stumbling, no bogging, no lean cough sputting and no needle adjustments. Transition is smooth from idle upward. I also noticed a deeper throb to the exhaust tone.

After about a 20-mile test trip, I increased my DAJ setting 1 click richer to accommodate the open no baffle exhaust configuration. I did not notice much difference till I hit mid RPM's and then it just was a hard rush that surprised me. The bike came alive pulling evere harder all the way up the RPM Range.

2 tanks of fuel since I installed the DAJ and I have been running it harder than normal around town. I have been really enjoying the new found power in the mid to higher RPM's. Yet to my surprise, my "around town" mileage has increased from 37mpg to 41mpg.

10/15/02: 6 months of running the Stock Headers & Barons Nasty Boys Slip On's with racing Baffles.

I have now installed the "Hard Krome Double D's 2.75" Big Staights" full exhaust system. They have a 1&3/4" headers and flow a lot more exhaust gas as compared to the the stock 1&9/16" headers. So far I have not had to change the DAJ settings.

The low end torque has increased and the 4k on up is a rush as the tach climbs to the mid 6k RPM. But lets face it ..... it all about the Sound's the HK's make! <GRIN>

Comments: The real advantage is the options. If I need more fuel at the top end or less fuel for installing my baffles with glass packing for long trips, (which would make the engine run rich), all I have to do is adjust the settings of the DAJ with a screwdriver, nice!

The product appears to work as advertised, and although some scoff at the technical lingo, it works. I have found this product to be a simple to install alternative to hard carburetor tear down and jet replacement. I can also see why some serious racers are using the DAJ as an enhancement to smooth out the power curve. It is a matter of understanding and using the technology to suit your needs, racing or just richen up a lean engine.

*Un-wanted Test:

I routed one DAJ Fuel Line in too tight of a bend. In a few months it kinked and limited the fuel supply to the front DAJ. The bike ran OK except when I jumped on the throttle it stumbled and acted like one plug was not firing?

1st I check my plugs and noticed the front looked leaner, so I looked further and found the crimped DAJ Fuel feed line. Changed and rerouted the line and it was back to running great. So simply put the product works. With a crimped DAJ fuel line the engine ran poorly without re-jetting, but with the DAJ fuel line un-crimped it runs strong.

In my humble Opion:

1 year later I did the DBAK and after jetting and set up, I added my "adjustable back pressure straights pipes" on in place of the HK Baffles. So I installed the DAJ to fill in any jetting holes and it is running great at the lowest setting.

*DAJ range of adjustment is diminished as less vacuum pressure is created by a wide open air kit like the DBAK or Maxair because of the removal of the airbox. The individual Pod type of Filters, will greatly reduced the DAJ adjustablity range.

*If you do some radical air modification or add some very large exhaust headers with the factory airbox, you will move beyond the DAJ adjustment range. Then you will have to open the carburetors and increase just the Main Jets a couple ranges and DAJ will take it from there with out all the other needle adjustment, etc.

Tony Anzalone 

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