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  1. Follow the recommended carb sync method for your bike. These instructions assume that you know how to prepare and adjust your bike.

  2. The sensors have a 3mm port. A 1/8 inch ID tube works great. You will need a plastic reducing coupler to connect to a tube that fits your bike. Yamaha uses 5mm. A 3/16” ID tube works great. Honda uses a 6mm port. A 1/4” ID tube works great. Some makes and models vary. Make a set of tubes that are consistent. It doesn’t matter which size tube is longer but cut, build and hook-up everything the same.

  3. With your bike prepared for sync, hook up your tubes to the carbs and the sensors.

  4. With the bike NOT RUNNING connect the device to the dc power source you are using, or if it is already powered on, press the reset button.

  5. NOTE: new versions of the software do not use a calibration sequence. Wait for the calibration sequence to complete.

  6. It is normal for the calibration to set the sensor readout within a point or two of each other. If all sensors are reading the same that means someone did a really good job soldering it all together and everything is in ideal condition. For the rest of us, just note the relative settings when the bike is off. The Digital Carb Sync Shield is designed to be forgiving to build quality. New versions of the software do not use a calibration sequence. The software code can be adjusted if desired.


  8. Follow the bike’s owners manual to adjust the carbs.

  9. Get the readings as close to each other as you can. A few points difference is fine. The sensors are more accurate than needed.

  10. It is okay to open up the throttle but remember that if your vacuum advance is disconnected the bike may miss at higher RPMs.

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Hot plate solder technique

To easily mount the sensors it is HIGHLY recommended to use the cheap solder paste method on a hot plate. A toaster oven can work, too. Even any fry pan on the stove top can work but check with the boss first. Getting the sensors well-mounted is crucial. After the flux burns off (about 7 minutes on this hot plate) a perfect silver solder job remains.

Sensors in paste before heating
Sensors in paste before heating

hot plate and solder paste

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All the parts

Small parts and LCD screen
Vacuum sensor
Black Label Board
Arduino Uno R3


The sensors and the Arduino board are worth shopping around for. Buy the rest from one source. The trick is to minimize shipping costs. The LCD and the small parts can be found at a decent electronics parts store (be sure of configuration compatibility for the potentiometer and reset push switch so they fit the board). Ordering from is the easiest and it beats running around looking for small parts.

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Useful information about the bootloader

An Arduino usually has a bootloader on it. When using one of the hex loaders you may or may not be loading or even overwriting the bootloader. That’s fine, it just takes up space, unless you are trying to load something from the IDE. Then the board needs to have a bootloader. Fortunately, the IDE has an option to first load the bootloader.

Sometimes DigitalCarbSync hex programs are supplied with and without a bootloader. Either will usually work. Sometimes the supplied hex program is too big to load directly if it also includes the bootloader. Just use the other version.

Here is some useful information about the bootloader.

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Source for plastic tube and couplers

We sell our stock of tube couplers at outrageous prices. Well, double-ish, anyway.

You may be better off buying directly from our source. They have lots of options.

It all depends on the number you want, shipping costs and convenience. If you are buying a board from us the shipping is flat rate so adding on the connectors may make sense.

These Luer connectors work. You can mix and match the sizes.

Here’s what we use: