Andy's Carb Cleaning Guide - s Carb Cleaning...Andy's Carb Cleaning Guide.doc April 04, 2012...

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  • Andy's Carb Cleaning Guide.doc April 04, 2012

    G:\Carbs\Andy's Carb Cleaning Guide.doc Page 1 of 6

    Carburetor Cleaning Guide Carb cleaning just the phrase alone is enough to make a V4 owner blanch and break into a cold sweat but it doesnt have to be. Any DIYer who understands why a wrench isnt for use as a hammer and what the difference is between a screwdriver and a pry bar can successfully clean their own carbs with care and attention to detail. Some inexpensive tools and supplies are need but beyond that there is a fairly simple recipe to be followed and a few basic precautions to be observed.

    Carbs function as part of the entire combustion system and interact closely with the other parts of the system. To get the best performance from your bike, carb cleaning needs to be part of an overall tune-up process. To minimize the amount of time it will take to get your bike into good running order it is necessary to do each step in order to establish the correct conditions for the next step. Doing the steps out of order will not produce the same results because of the interaction between the parts of the system.

    I encourage you to take pictures of each step to serve as a reference when it is time to re-assemble the components. This is especially useful for cable routing and linkage connection reference. I have inserted an icon where I think a picture may be helpful. This guideline is based on my 1985 V45 Magna but is general enough to be widely applicable. I have inserted an icon where I think models typically vary. The Carb Cleaning Recipe The tune-up steps:

    1. Before removing carbs; a. lift gas tank (make sure not more than 2/3 full), b. remove air filter, filter box, metal screen under box, c. drain and remove the radiator, d. remove heat shield mounted on the air box on the radiator side, e. turn the fuel petcock off, f. remove the gas line from carb #1 and catch gas in a container.

    2. Removing carbs; a. note orientation of the isolator (rubber boots) clamps and loosen all 8 of them,

    b. pull the carbs and airbox upwards until loose (difficult by hand - try ONE tie down threaded under the airbox and over the top of the frame or anchored to the handlebars accompanied by hand pressure back and forth on each side) until the carbs come loose as a single unit,

    c. remove the isolators and clamps, d. wiggle, tilt, and the slide carbs to the left side of the bike, e. note the cable routing and disconnect the choke and two throttle

    cables, f. undo the single clamp bolt (8mm) holding each of the two coolant

    crossover tubes, g. work each tube straight out of the heads. With the clamp removed they

    are only held by the o-rings on each end. If you pry them be gentle they are thin walled, and pry each end equally so they dont twist and jam. If they jam, gently push the

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    out end back in level with the other and then continue. Dont be rough if you distort the ends you will have trouble getting a leak-free re-installation,

    h. remove the carbs out the right side of the bike. Some twisting and tipping may be needed but force isnt necessary unless you are doing something wrong,

    i. with carbs off the bike, drain any remaining gas from them.

    3. Before disassembling the carb-airbox unit;

    a. Note which carb is which carb number. The carb for cylinder #1 is carb #1. On my bike Cyl #1 is rear left, #2 is front left, #3 is rear right, #4 is front right. You can use a marker or scriber to mark the carb number on the outside of each carb as it is easy to mix them up especially if this is the first time you have cleaned them.

    b. Prepare a container for each carb and the pieces removed from that carb a plastic tray is excellent but a separate area on the workbench is sufficient. Do not mix the parts between the carbs as there are subtle but critical differences. Label each container with the carb number.

    c. Prepare an additional common container for linkages and other external parts, d. Note which carb number fits where in the airbox. If you want, use a marker to label the inside of

    the airbox.

    4. Disassembling the carb-airbox unit; a. Start by removing the 2 screws (Phillips #3) per carb from the inside

    of the airbox. If you use an impact driver be careful not to damage the thin-wall cast body of the airbox,

    b. Separate the carbs as a group from the air box and lay them on the bench, (Note carbs #3 and #4 are incorrectly identified in the picture)

    c. Remove each of the rubber trumpets and place it in the appropriate carbs container,

    d. Carefully note how all the linkages and connecting tubes run. Pictures are a definite plus here. Consider using paint marker dots to identify which end or face is oriented where.

    e. Disconnect all the linkages and connecting tubes, placing the springs, washers, nuts, etc. into the common container.

    5. Disassembling each carb;

    a. Slider - Remove the 3 Phillips screws from the domed chrome top hold the top in place against a light spring pressure while removing the screws. Before moving the top, look carefully around the edge and note where the little raised channel is located.

    b. Lift the top off, remove the coil spring and place both in the container, c. The black rubber diaphragm is delicate and EXPENSIVE treat it with

    care while removing it along with the slide and main jet. Put the carb down and hold onto the slide,

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    d. Remove the needle from the slider by pressing down on the plastic piece inside the bottom of the slider and turning it 90 degrees. It should now lift out, releasing the needle. Make a special note of any washers under the head of the needle and remove them with the needle,

    e. Place the slide with diaphragm in a protected place a dedicated margarine container within the carb container would not be going overboard.

    f. Float bowl - Turn the carb over and remove the 4 screws holding the bowl. The bowl will likely be stuck in place, very gently pry it apart taking care not to damage the mating surfaces or the float bowl gasket. Inspect the gasket, if it damaged or flattened so that it does not protrude above the mating face of the float bowl, it needs to be replaced,

    g. Note the orientation of the float and use needle-nose pliers to pull the float pivot pin completely out, removing it and the float,

    h. Remove the float valve, screen, and washer from the carb body under where the brass tang of the float sat,

    i. Remove the main jet (slot head), main jet holder (hex body), and the slow jet from the carb body. One piece is pressed in and is not removable,

    j. Choke Remove the nut and washer from the top of the activating shaft for the choke. Pull the black plastic tube up and off the shaft which frees up the lower portion of the shaft so it can be removed from the two fingers holding it. Unscrew the plastic nut around the choke plunger rod and work the shaft forks out of the groove on the end of the plunger. Remove the activating shaft, plastic nut, and plunger. Hopefully yours will not have the woodscrew added by a creative PO to replace the brass nub on the end of the enrichner valve likely broken off during an incorrect disassembly attempt.

    k. Butterfly valve Note the location of any markings on the round butterfly valve it has a top-bottom and inside-outside orientation that must be maintained when it is reassembled or it will not fit or operate correctly. The valve is secured to the throttle shaft by two small Phillips head screws. It is essential to have a #3 Phillips screwdriver that fits the screw heads tightly or they will be stripped when you try to remove them. The other end of the screws has been slotted and spread apart slightly to ensure they do not vibrate out of the throttle shaft. Remove the screws,

    l. Turn the throttle shaft 90 degrees and pull the butterfly valve out, m. The throttle shaft is now free to be removed, n. Around where the throttle shaft enters the carb body there is a

    pressed in metal ring covering a felt seal. Use a small screwdriver to remove the ring and washer without damaging either of them. The seal can be damaged by the cleaners and is no longer available as an OEM part possibly not as an aftermarket part either,

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    o. Pilot needle jet The pilot jet screws into the outside of the throat of the carb near where the isolator (rubber mounting boot) stops. It may be covered by a thin aluminum plug pressed into the hole over the pilot jet or that may have been removed during a previous cleaning. If the plug is there, remove it by drilling a small hole through it and inserting a dental pick or wood screw and pulling the cap out,

    p. Under the cap is the jet. Use a small slot screwdriver to screw the jet IN until it bottoms gently, counting the turns to the nearest 1/8

    th

    turn. Record the number of turns for use later they can be different for each carb so do not mix them up,

    q. Unscrew the jet and remove it along with the spring, washer, and o-ring. If the washer and o-ring do not come out it is necessary to hook them and pull them out with a small piece of copper wire or other soft hook that will not damage the seat.

    r. If you havent done it already, now is a good time to order any replacement parts you need. (The screws for the float bowls and diaphragm housings are size M4x0.70 pitch. length is about 1 inch for float bowls and .75 inch for diaphragm. Do not use longer screws as those for the carb bowl will hit and crack the plastic fuel tran