There are many bolt-on performance upgrades available for the Harley XLH 883 Sportster, but owners looking to go deeper into the engine usually look to the 883 cc-to-1200 cc conversion, frequently with a larger jet set, low-restriction air cleaner and exhaust, a performance ignition module with programmable rev limiter and performance cams. This maximizes the displacement for the engine block, but imposes the “Harley Tax” -- having to spend money to remove the restrictions to the intake and exhaust so the engine breathes as designed.
Things You'll Need
- No.3 Phillips screwdriver
- Allen driver set
- Ratchet set
- Flat-head screwdriver, thin blade
- Gasoline container
- Open-end wrench set
- No.2 Phillips screwdriver
- Jet tool
- No.44 jet
- No.180 jet
- Carburetor gasket set
- Inch-pound torque wrench
Remove the two air cleaner cover retainer screws, using a No.3 Phillips screwdriver. Pull the cover off the backing plate. Remove the air cleaner element screws and remove the element.
Remove the two large breather bolts, using an Allen driver and ratchet. Loosen the three backing plate-to-carburetor screws a few turns at a time until the backing plate comes free. Remove any remaining emissions tubes from the backing plate. Remove the backing plate from the engine. Remove and discard the gasket.
Slide the rubber throttle cable adjuster covers down on the cable, and collapse both the pull-open and pull-closed cable adjusters. Remove the throttle cables from any routing clips -- such as under the ignition switch housing -- to allow enough slack to slightly separate the carburetor from the engine.
Ensure that the fuel petcock is in the "Off" position. Find the carburetor drain screw at the bottom of the bowl. Hold a container under the carburetor and open the drain, using a thin, flat-head screwdriver, until the fuel in the bowl and the line drains out, which should be about 5 to 6 tablespoons, then tighten the drain screw firmly. Carefully remove the petcock fuel line clamp or tie and then pull the fuel hose from the petcock.
Loosen the knurled enrichener drag ring on the outside of the bracket. Using an open-ended wrench, loosen the enrichener adjuster backing nut a few turns and slide the enrichener cable adjuster down and out of the bracket. Locate the small, black carburetor bowl overflow tube, and take note of its routing, then pull it loose from its routing.
Pull the carburetor out of the intake manifold and away from the engine slightly to access the throttle cable ends. Disengage the cable ferrules from the carburetor and pull the throttle cables from their bracket towers. Carefully pull the carburetor from the engine while guiding the enrichener cable and knob around the intake manifold. Remove the carburetor-to-intake manifold gasket from the carburetor and install it back on the intake manifold.
Disengage the accelerator pump pushrod from the cam on the carburetor body. Invert the carburetor and remove the four fuel bowl screws, using a No.2 Phillips screwdriver. Carefully remove the bowl, gasket, and accelerator pump discharge tower O-ring.
Remove the jets from the carburetor, using a jet tool. Install a new 44 jet in the intermediate jet port. Install a new No.180 main jet. Carefully tighten both jets, using a jet tool.
Install a new accelerator pump tower O-ring on the tower, and lay the new bowl gasket in its groove on the bowl lip. Move the bowl into position on the carburetor body. If the accelerator pump pushrod came out during disassembly, guide the pushrod into its tower on the bowl. Ensure that the bowl gasket has not rolled out of position, and tighten the bowl screws securely.
Install the throttle cables in their bracket towers. Feed the fuel hose enrichener cable and knob over the intake manifold. Install the fuel hose using a new clamp or tie. Install the enrichener cable adjuster in the bracket and tighten the adjuster backing nut, using an open-ended wrench just until it is secure. Tighten the knurled adjuster ring to adjust the enrichener cable tension.
Install the new backing plate-to-carburetor gasket on the back of the backing plate. Use the threads of the screws to hold the gasket in position. Install the backing plate on the carburetor and torque the backing plate-to-carburetor screws to 40 to 60 inch-pounds, using an inch-pound torque wrench. Hold the assembly near its position on the engine and connect any emissions tubes. Push the carburetor into the intake manifold until the backing plate bottoms out in position. Install the breather bolts through the backing plate and torque them to 84 to 120 inch-pounds. Install the air cleaner element and screws, and torque them to 40 to 60 inch-pounds. Install the air cleaner cover and torque the screws to 36 to 60 inch-pounds. Route the carburetor bowl overflow drain tube in its original position.
Tips & Warnings
- These are standard jet sizes for this procedure. However, if there is a flat spot or a lean misfire at certain throttle settings, then the jets may have to be adjusted one or two sizes. There may also be some adjustment necessary to account for backpressure variations with different exhaust systems and air supply restriction variations at the air cleaner.
- Anti-Reversion cones or power cones are recommended when using a low-restriction exhaust systems, to prevent power loss due to exhaust gas reversion, which is a common problem with low-restriction exhausts.
- Do not attempt to back one of the backing plate-to-carburetor screws out fully before the others, or try to back any of the screws all the way out. The screws are captive in the backing plate and damage will occur to the screw bosses if the screws are backed out fully.
- Do not attempt to remove or install jets with a regular flat-head screwdriver. Damage can occur to the orifice and artificially reduce the size of the jet. Another approved method for removing jets that are not tucked away in a housing is to grip the outside of the jet with pliers to break the jet loose. If you use this method, ensure that you only grab the jet, and not the jet-tower as well.