CX Master Carb Kit (B)

Randakk Master Carb Overhaul Kit® for Honda CX500 (and variants) includes everything you need (and nothing you don't!)
$105.99 105.99
In stock
Only 1 left


A, B & C Versions Available. There are important component differences, so be sure to order the correct version for your bike!

See: Additional Fit Details courtesy of good friend, the late, Dick Smith (aka Dick in Raleigh). Includes information to help you determine if you have an accelerate pump!

Thinking of buying an "A" kit just to save money? Think again! "A" kits have different air cut-off valves and different idle passage plugs and are incorrect if your bike actually requires a "B" or "C" kit! See: Additional Fit Details

Version Models
Version A All CX500s without accelerator pump except Eurosport models.
Version B
All CX500s with accelerator pump
All GL500s
Version C All 650s (both CX and GL versions)

Note: If you have a Eurosport model (CX500E or CX650E), contact us BEFORE YOU ORDER for special instructions.

Randakk Master Carb Overhaul Kit® for Honda CX500 (and variants) includes everything you need (and nothing you don't!) for a comprehensive carb overhaul on carbureted CX500, CX650, GL500 and GL650 models produced during 1978-1983 (see Fitment Chart below). The kit includes parts for both carbs.

This kit is proprietary to Randakk's won't find this available anywhere else at any price. Sourced with the best available parts from 3 continents and combined in a unique combination that represents real value.

Unlike other kits on the market, this kit includes pesky carburetor body side-to-side sealing o-rings that seem to give so much trouble on units that have been parked for awhile (details below).

Note: The round o-rings in each Master Kit is made of Viton rather than ordinary nitrile (Buna-N) as found in other aftermarket carb kits. Viton is superior to nitrile in terms of:

  • Heat tolerance (400 degrees F vs. 250 degrees F)
  • Compression set
  • Permeation

Did you know that one good case of severe engine overheating can ruin the carb o-rings found in ordinary kits? Randakk's o-rings are the best available!

Randakk's CX500 Master Carb Overhaul Kit? -Version B shown

(Version C has similar components)

(Version A omits accelerator pump in lower right of picture)

Unlike ordinary aftermarket kits, each Randakk kit provides everything listed for both carbs + other items required for splitting and re-joining the carb assembly to replace the cross carb main fuel transfer tubes as well as the accelerator circuits. I even include rebuild kits for the air cut-off valve and accelerator valve as required for each application.

Only the highest quality items are included. This kit has been thoroughly tested. This collection represents the best value available in the market. Trust me, you will need everything in this kit to do a proper overhaul of your carbs.

Here's what you get:

Viton O-rings:

  • 2 - fuel (idle) mixture screw (2.8 x 1.1 mm)
  • 2 - float bowl drain screw (4.3 x 1.3 mm)
  • 2 - CV Slide Top Limit Plug (6.9 x 1.3 mm)
  • 1 - Accelerator pump passage at float bowl (5.0 x 1.3 mm)*
  • 2 - Main Fuel Transfer Tubes (5.8 x 2.0 mm)
  • 2 - Accelerator Fuel Transfer Tubes (3.8 x 2.0 mm)**
  • 2 - Intake Manifold (40 x 2.6 mm)...slightly thicker cross section than the OEM specified o-ring for better fit and function

    * as required

    ** included in all kits, but not needed for "A" versions.

Float Bowl Gaskets - 2 of each:

  • Constructed of superior Viton material to resist the components of modern gasoline.

Miscellaneous Parts:

  • 2 Air Cutoff Valve Overhaul Kit (unique fitments for A, B & C versions)
  • 1 Accelerator Pump Overhaul Kit (unique fitment for B & C versions only)
  • 2 idle mixture screw washers
  • 6 float bowl screws (4 x 16 mm)
  • 1 mm cotter pin for accelerator pump linkage - 1 supplied (simple item, but hard to find elsewhere) ** included in all kits, but not needed for "A" versions.
  • Viton rubber blanking plugs - cover access to idle fuel jet
    • 2 "Small" Blanking Plugs supplied with Version A kits
    • 2 "Large" Blanking Plugs supplied with Version B & C kits

    Parts Count:

    • Version A - 29 total parts
    • Version B - 33 total parts
    • Version B - 33 total parts


    You will need access to good reference material for a successful rebuild.

    A recommended reference option: Larry's Guide to Rebuilding the Keihin CX/GL Carburetors by Larry Cargill. This one is packed with useful info ration and has great COLOR photography.

    Purchase this booklet directly at: Larry's Guide to Rebuilding the Keihin CX/GL Carburetors

    Another good option:

    Mike Nixon's booklet, Cleaning the CX500 Carburetor. This 35 page booklet is also recommended. 110+ black and white photos and illustrations. Covers the CX500 and all variant models.

    Purchase this booklet directly at Mike's Book Nook.

    Artwork courtesy of Mike Nixon

    Randakk's also recommends that you refer to the official Honda Factory Workshop Manual. There is some critical information there on rejoining and aligning the carb bodies to prevent binding of the throttle and choke shafts...very important!

    Randakk's Master Kit includes all o-rings needed for renewing the fuel transfer tubes (main and accelerator).

    Notes: No jets or jet needles are supplied with this kit. Randakk's experience is that these can normally be cleaned and re-used. Aftermarket needles are not sized as accurately as the OEM needles and may introduce lean / rich problems where none existed. Unless your needles are worn or bent, Randakk's recommends reusing them. If you try to buy jet needles from Honda, you'll discover that they are only available as a set which includes the CV slide, cap and jet needle. The price will make you faint! If you need jets, buy aftermarket kits such as those from K&L or spring for the genuine Honda bits.

    These carbs have non-removable float seats (a mistake by Honda in Randakk's opinion!). There are no float needles in the kit. Many aftermarket rebuild kits include float needles of dubious quality. There have been many problems with these aftermarket items. Most related to the aftermarket float needles being incorrectly sized (too short) resulting in unreliable (or nonexistent) fuel shutoff. Some are OK. The rubber tips and seats on the OEM item will last nearly forever and can usually be cleaned and reused. Randakk's doesn't include these items to give you a choice on what to buy if you think new ones are needed.

    If you need new float needles, you can buy the OEM item and not have a worry. The Honda part number is 16155-413-751. You will need to order 2 of these. Or, take a slight gamble and go with aftermarket float needles which are available at reasonable cost from numerous suppliers.

    Considerable skill is required to install this high quality kit correctly. Since Randakk's cannot control this important variable, there is no warranty. Rest assured that they are of the highest quality materials and workmanship. Each kit has been carefully packed and inspected to ensure that all items are included.

    Warning: Please open the package very carefully when it arrives. Many of the parts are very small so take appropriate precautions. If you chose to open the package in the dark over your gravel driveway, after 1 or 12 beers, please don't later complain that you are a "few o-rings short." Seriously, do be careful when you open the package!

    CX Model Identification

    • Early CX500s have wide-spaced, parallel carbs with no accelerator pump. The carbs are spaced at 160 mm on center. These take Randakk Master Kit A.
    • Later CX500s with accelerator pumps (spaced at 160 mm on center) and all GL500s. All GL500 carbs are close-spaced at only 100mm on center and the carbs are parallel. These take Randakk Master Kit B
    • All 650s have carbs mounted on an angled bracket (not parallel). These take Randakk Master Kit C.

    For obvious reasons, Turbo models of these bike are not supported...those are fuel injected!

    Not sure if you can handle your own rebuild? For information on Randakk's Approved Honda Carb Rebuilder Program

    See also: Additional Fit Details courtesy of good friend, the late, Dick Smith (aka Dick in Raleigh).

    To read more reviews on this and other products visit our Review Site,

    Is Universal Part: No

    OEM Number(s): N/A

    Motorcycle Fitment:

    • 1978 Honda CX500 CX500
    • 1979 Honda CX500 CX500
    • 1979 Honda CX500 CX500C
    • 1979 Honda CX500 CX500D
    • 1980 Honda CX500 CX500C Custom
    • 1980 Honda CX500 CX500D Deluxe
    • 1981 Honda CX500 CX500C Custom
    • 1981 Honda CX500 CX500D Deluxe
    • 1981 Honda GL500 GL500
    • 1981 Honda GL500 GL500I Silver Wing Interstate
    • 1982 Honda CX500 CX500C Custom
    • 1982 Honda CX500 CX500TC Turbo
    • 1982 Honda GL500 GL500
    • 1982 Honda GL500 GL500I Silver Wing Interstate