Installing a Genesis Carburetor

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Written by Randy Fox (randysgym)   
Sunday, 06 September 2009

Removing the Old Carb, Manifold, and Throttle Cable

This section describes how to remove a stock, Road Star carburetor. If you have a different carb, your removal process will differ somewhat.

Remove the gas tank (Refer to the Tank Removal article if needed).

Remove the upper motor mount from between the cylinders on the left side of the bike (2 bolts to the frame, 2 bolts to the heads). Note: If you still have a fuel pump and/or choke cable attached to the upper motor mount, the pump must be removed first, and the choke cable must be detached from its mounting bracket, as well. Refer to the Service Manual. See photo below.

yamaha road star roadstar, genesis carburetor install

Important Note: You should not use a fuel pump with the Genesis carb.

If you have a fuel pump and/or choke cable that have been relocated from their stock locations, remove the fuel pump and detach the choke cable end. Also, remove the fuel filter and fuel hoses.

Remove your breather (air cleaner) from the carb and from the cylinder heads. Also detach the idle adjuster. Refer to the Service Manual for details.

Next, detach the throttle cable/s from the carburetor. To do this, you must loosen the cable adjustment nuts (the ones along the cable, near the carb) to a large degree, then work the cable-casing end-fitting free from its bracket, then work the inner-cable end-barrel free from its pulley on the carb.

Next, disconnect the TPS. To do this, follow the wire harness from the carb to the left side of the frame. There is a TPS wiring connector along the frame at this point; disconnect it. See photo below. Tip: Do not unscrew the TPS from the carb.

yamaha road star roadstar, genesis carburetor install TPS

Note: There is no known way to connect a TPS to the Genesis carb. If you wish to keep the Road Star's TPS function, you will need to install a standalone driver. See the Fabricating a TPS Driver article for details.

Now unplug the carb heater wire from the carb. Be a little careful as you do this, as its attachment is a bit delicate. See photo below.

yamaha road star roadstar, genesis carburetor install

Finally, you’re ready to remove the carb from the bike. Loosen the big hose clamps from the manifold connection at back-side of the carb. Then wiggle the carb loose from the manifold.

Next, remove the intake manifold from between the cylinders. It is held in place with four bolts. Some aftermarket manifolds must be removed by sliding them toward the right side of the bike, rather than up and out. Coax it; wiggle it; do not force it.

Once the manifold has been removed, be very careful not to drop anything into the cylinders’ intake ports. If you do drop something into a cylinder, and you can't reach in to successfully retrieve it, the cylinder head may have to be removed (a much bigger project) BEFORE the bike can be started, or you risk complete engine failure (VERY expensive). Tip: Stuff a clean latex glove or rag loosely into each intake port of the engine to prevent accidentally dropping something into the engine. Just be sure you remove them before installing your new manifold.

Store the intake system, including the old manifold, carb and fuel pump assemblies. However, be sure to drain the gasoline from all parts, and let them sit out for several days before storing indoors. Otherwise they may stink and create a fire and/or health hazard.

Removing the Old Throttle Cable

You can skip this section if you will not be replacing your throttle cable/s.

Depending on the age and condition of your throttle cable/s, you might want to replace it/them. If you still have a throttle return cable, you may also want to consider discarding it.

Opinion: I think the throttle return cable is an outdated feature, still legally required of manufacturers, that adds no valuable functionality or safety. It made sense back in the days when carbs were made differently, return springs were prone to breaking, and cabling wasn't nearly so durable yet flexible. I eliminated my throttle return cable soon after purchasing my Roadie in 2003, and have enjoyed smoother throttle control, less handlebar clutter, and one less thing to go wrong, ever since. In fact, while the Genesis carb does accommodate a throttle return cable, it performs no mechanical function.

If you will be replacing your old throttle cable/s, you must remove it/them. To do this, you must remove the right hand-grip assembly. But, to do that, you must first remove the front brake handlebar assembly, in order to gain access to the lower screw that secures the throttle grip assembly.

Once you have removed the two hex (allen) bolts that clamp the brake assembly to the handlebar, you will need to temporarily tape, or tie the brake assembly to the handlebars (or some other handy, high place). Be careful not to stress the hydraulic hose (or scratch any chrome).

The right-hand control box and throttle control assembly is held together by two phillips ('+') screws. Be very careful removing -- and later installing -- these, as the screw-heads are easily stripped. Also, the lower screw is hidden behind a gray wiring cable. You can work the cable free of its entry guide-channel; just be careful not to stress the cable.

Once the screws are removed, the two halves of the control box may easily come apart, so be ready. Also, internal wiring for the starter and kill switches will get exposed, so a bit of care is required. Tip: The internal wiring is held in place with ties and clamps, so don't worry about a wiring mess. Just be careful not to stress the wiring (or pinch it upon reassembly).

Removing the throttle cable is easy from this point. Refer to the Service Manual for details. Just note that the phillips ('+') screw that clamps the throttle cable end-fitting to the control box is easily stripped, so be careful.

Put your new cable/s on using these instructions in reverse, although you may wish to wait until the Genesis carb in installed, as described later in this document.

 
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