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How to Rebuild Carbs on a Motorcycle

How to Rebuild Carbs on a Motorcycle

Jul 24, 2019

If you just bought an old motorcycle for a DIY rebuild project or want to revive that classic V-twin motorcycle that has been sitting in your garage for years, chances are the carburetors are all varnished up, and require thorough cleaning. Learning how to rebuild carbs on a motorcycle can take a bit of learning but is time-saving and cheaper than replacing it with a new one.

By following some basic steps, dismantling and rebuilding a motorcycle carburetor is relatively simple and is even more rewarding when the bike runs smoothly afterward. Before you get started, take a number of precautions: wear safety glasses and safety gloves and work in a well-lit and clean area. Here’s what you need to do to rebuild carbs on a motorcycle:

Prepare and Remove the Carburetors

Philips head screw set

Get your motorcycle service manual and read through it to understand the exact steps you’re supposed to take to remove the carbs from your motorcycle and also taking them apart. To remove the carbs, disconnect the lines attached, loosen the screws used to tighten the manifold clamps, remove the airbox, and pop of the carburetor rack.

The most important thing when learning how to rebuild carbs on a motorcycle is to take things slow and keep things organized. Make sure that you also have a dedicated workspace before you start disconnecting the carburetors from their rack and working on each of them individually.

Disassemble the Carburetors

Removing carburetor

With your rack of carburetors off the bike, start disconnecting them by simply unscrewing them from the rigid mounting plate. In most cases, you’ll find 2 or 4 screws holding each carburetor in place. Before getting to each carb, you may have to remove the choke rod as well as the throttle shaft. Make sure you have separate containers for each carb in your workspace.

This is important as you’ll want to keep all the internal components of each carb with the body you’ve disassembled them from. Remove any rubber parts and set them aside before you use any type of cleaner. This is an important step in learning how to rebuild carbs on a motorcycle, especially if your throttle slides work with a rubber diaphragm.

Be careful when removing the throttle slide as the rubber diaphragm could be stuck if the bike has not been in use for too long. If the slide is stuck, you can soak it with penetrating oil or use a heat gun to apply some heat. This will it east to unscrew the throttle slide tops and float bowls. Accessing and removing most of the jets is possible from the bottom of the carburetors.

Remove any plastic or rubber carb floats and o-rings before using carb cleaner. When it comes to removing the air and pilot screws, turn them in individually until they stop and count the number of turns. When reassembling the carburetors, you’ll have to match the same number of counts for correct installation of the screws.

Remove the carb jets and be cautious to avoid stripping them or breaking any legs or supports with the carb body. Use carb cleaner to gently loosen up any varnish that may be fusing components together. Be sure to check if jets in your carburetors can be removed or not, just to be sure. Your service manual on how to rebuild carbs on a motorcycle should guide you on this.

Clean Your Motorcycle Carburetors

Cleaning carburetors

After you’ve removed all vital components, you can now dip the carbs in the recommended carb cleaner to get rid of varnish. After some soaking, remove the carburetors and wipe off any excess carb cleaner, then spray each passage with a recommended spray carb cleaner. For the smaller passageways, use a thin wire. Again, safety is crucial when handling carb chemicals.

Rebuilding the Motorcycle Carburetors

Custom motorcycle parts

With your carburetors clean, it’s time to rebuild them. During the disassembling and cleaning process, you should have already noted any components that were worn out or damaged so you can get the right replacements. To make this process easier, it’s advisable to buy aftermarket carburetor rebuild kits.

In any case, if you were able to thoroughly clean the jets and reuse them in your carburetors, do so, as there can be a slight difference between aftermarket jets and OEM parts, causing tuning issues. Washers, gaskets, and O-rings from aftermarket carburetor rebuild kits can be used. Rebuilding a stock configuration is considered the best way to go when it comes to understanding how to rebuild carbs on a motorcycle.

Shop Custom Parts for Your Bike

Rebuilding your motorcycle carburetors is not the end of the road. Your bike’s performance relies on a combination of customizable parts and accessories to make the riding experience thrilling. Shop the parts you need to improve your bike such as throttle assist and basic maintenance accessories like cleaners and polishes at West End Motorsports today.

Have any questions? Call us now at 570.992.1113.