Honda DOHC Motorcycles Randakk Master Carb Overhaul Kits®

World’s Best DOHC Kit!

Randakks Master Carb Kit 100-1223 Cover


The architecture of these carbs is very similar to the GL1100, CBX, and CX-500 carbs that we have been supporting with our proprietary Master Kits for quite some time. After fielding numerous requests, Randakk’s has decided to extend coverage to these models.


This kit is proprietary to Randakks…you won’t find this available anywhere else at any price. 


Unlike ordinary aftermarket kits, each Randakks kit provides everything listed for all 4 carbs plus other items required for splitting and rejoining the carbs to replace the cross-carb fuel transfer tubes.

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



DOHC Model Identification


  • All 1979 CB750 DOHC Fours with original carbs will require our 100-1223 kit.
  • All 1980 – 1983 CB750 & CB900C DOHC Fours with original carbs will require our 100-1224 kit.
  • All 1981 – 1982 CB900F DOHC Fours with original carbs will require our 100-1225 kit.
  • All 1983 CB1000C & CB1100F DOHC Fours with original carbs will require our 100-1226 kit.



Kit Components


The contents of each DOHC Four Master Kit are identical except for variations on the Accelerator Pump and Air Cutoff Valves

Randakks Master Carb Kit 100-1223 Components


Viton O-rings:


4x  fuel (idle) mixture screw (2.8 x 1.1mm)

4x  float bowl drain screw (4.3 x 1.3mm)

4x  CV Slide Top Limit Plug (6.9 x 1.3mm)

1x  accelerator pump passage at float bowl (5.0 x 1.3mm).

6x  Main Fuel Transfer Tubes (5.8 x 2.0mm)

6x  Accelerator Fuel Transfer Tubes (3.8 x 2.0mm)

4x  Float Bowl Gaskets – 4 of each – Constructed of superior Viton material to resist the components of modern gasoline.


Miscellaneous Parts:


4x  Air Cutoff Valve Overhaul Kits

1x  Accelerator Pump Overhaul Kit

4x  idle mixture screw washers

12x  float bowl screws (4 x 16mm)

1x  1mm cotter pin for the accelerator pump linkage – simple item, but hard to find elsewhere.

8x  Viton rubber blanking plugs – cover access to idle fuel jet (2 sizes supplied to cover all variants).

8x  high quality, plated M3 x 6mm (0.5 pitch) panhead screws for securing choke butterflies


Parts Total: 66 total pieces



All O-rings Are Not The Same!


The round o-rings in each Master Kit are made of Viton rather than ordinary nitrile (Buna-N) as found in other aftermarket carb kits. 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!


Viton is superior to nitrile in terms of:

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

We even include rebuild kits for the air cut-off valve and accelerator valve as required for each application.

cx500 accelerator pumpcx500 air cut off valve






You will need access to good reference material for a successful rebuild, such as 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!







“…I’ve received and installed the DOHC-4 Master Carb Kit. It arrived Monday!! Given the holiday, I was very surprised. Everything went together without a hitch. I have a couple other items to address before firing the bike up, but wanted to let you know the kit was perfect. The bike (1980 CB750C) had been sitting in a barn for 10 years and a field for 10 years before that, so all the o-rings and such were hard and nasty. Your kit was just the ticket.”


“Well, I’m fully back on the road now and I’m still impressed with the kit. I’ve got about 250 miles on it since installing your DOHC-4 Master Carb Kit. No crazy leaks or anything and the carbs work as good as they did from the factory I’m sure.”


Stan Blosser – Coopersville, MI





Quick Notes:

No jets or jet needles are supplied with our kits. These can normally be cleaned and reused.

No float valve/seat assemblies in our kit

All kits include 8 rubber blanking plugs that cover the access to the idle fuel jets on most models. Supplied are 2 sizes to cover all variants. Honda issued a few “oddball” versions of these carbs which require a slightly larger OD blanking plug. Per Mike Nixon: “I have noticed on a few DOHC carbs, for example, early 900C and the non-U.S. model 1100R, the standard size rubber plug on these 3-jet carbs does not fit correctly and the larger CX series plug must be used.”

Confusion regarding the so-called “2-jet” DOHC-4 carbs: “2-jet” carbs were found on a minority of DOHC-4 models…notably the CB1100Fs. These have only one main jet and a removable idle jet not covered by an idle passage plug. Passage plugs are included in all Randakk kits, but removable idle jets (without a cross-drilled port to the main jet tower) should never be covered by an idle passage plug because they feed directly from the float bowl. Generally, there is no cross-drilled passage from the main tower to feed them as in 3-jet carbs. However, there are very few anomalous DOHC carbs with removable idle jets, that do have a cross-drilled port to the main jet tower. These DO need an idle passage plug – usually the larger OD version that are supplied.

The choke butterflies must be removed during the disassembly of these carbs to renew the side-to-side transfer o-rings. The staked OEM choke butterfly screws are very difficult to re-use. You will need to use some medium-strength Lock-Tite to secure my screws.

Considerable skill is required to install this high-quality kit correctly. Since Randakk’s cannot control this important variable, there is no warranty on these. 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.


Not sure can handle your own rebuild? Then, check out Randakk’s Approved Carb Rebuilder Program.


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


Leave a Reply

Your email address will not be published. Required fields are marked *

© Copyright 2024 Randakks Cycle Shakk

Top ↑