How-To: CB350 CB400 CB500 CB550 CB650 Carburetor Rebuild
Are your CB carbs in need of a rebuild or cleaning? Do you need to fully degang all 4 carbs in order to replace those fuel joint tee o-rings? Looking to tune your carbs for pod filters or aftermarket exhaust?
In this 1 hour 10 minute long video, I show you how to fully disassembly and reassemble the carburetors.
Tools
You don’t need any special tools for this job, however I highly recommend using JIS screwdrivers. Also, using an auxiliary fuel tank to wet test them for any leak before installing them is a good idea.
Vessel Megadora 980 Impacta P2x150 #2 JIS Impact Screwdriver
Vessel 125943 908 P3x150 JIS Impact Screwdriver
Motion Pro Carburetor Adjusting Tool – Do yourself a favor and buy this tool, it will make synching so much easier.
Parts
For the rebuild kits, I ordered OEM parts, which included all the gaskets and o-rings. I also ordered OEM float valve assemblies. Below are some other parts that you will need.
Motion Pro 12-0053 Tygon Black 1/4″ x 3′ Premium Fuel Line – For the fuel lines. The OD fits perfect through the front plate.
Motion Pro 12-0050 Tygon Black 3/16″ x 3′ Premium Fuel Line – For the vent tubes.
Shaped Float Bowl Gaskets – The stock or round o-rings that come with most kits are impossible to install. I prefer to use these .
Cleaning Methods
I don’t cover the actual cleaning of the carburetors in this video. There are several methods you can use to clean them and are covered here.
Jetting Specs
Since this video covers several models, here is what I found actually works pretty good when you are running air pods and a free flowing aftermarket exhaust:
Pilot jet – one size leaner. For example, if stock is a 40, then I found a 38 to work pretty good. This goes to show that the stock air box flows pretty good at low RPM.
Pilot air screw – the air screw will probably end up at about 3/4 turn out.
Needle clip position – lower the clip one notch to allow more fuel in the 1/4 to 3/4 throttle range. This is where the pods flow more air.
Main jet – Bump up the mains 2 sizes over stock.
Your results may vary depending on parts used and where you are located.
Mathew, I bought the cb350/400 carb overhaul videos from you some time ago (last year). If you records are intact can you check that I did and send me part 2 again. I have lost part 2, still have part 1.
regards,
Baz Ford
I resent a receipt, check your email.
Hey Matthew,
Awesome video! I rebuilt my carbs using this video and I appreciate the work you’ve put into these! My only question is:
The wide double sided washers that connect the linkage between carbs 1&2 and the one that connects carbs 3&4 keep snapping in half when I start the bike. I’m doing a pretty good bench sync before running the carbs. So I know they are fairly close, and syncing them with the manometer is easy, but they always snap upon my first few starts. Do you know what I’m doing wrong? Does it really matter if they break? I ran it all summer with both washers snapped and really had no issues.
Thanks for any help you can provide.
Thanks for the compliments on the video!
Please email me pics of the washers you are talking about.
The video title lists CB650 carbs, but you don’t mention them as being covered in the video. Since those are the carburetors I will be working on I wanted to be sure they will be covered, before buying the video.
Only covers cb650 79-80 mechanical slide carbs
Matthew:
I have an 1982 cb 650. I would like to restore this bike, it’s all there with 13knon it. I have the service manuals. I have two questions.
1). Does this cover that model? ( pre buy )
2) Where do I get parts? The little rubber T between the carbs are cracked and non usable, let alone gaskets. I web search and all I see are full gasket kits which I believe only cover the engine.
I would appreciate any recommendations in getting me started on this project.
Thank you.
Bart Ransom.
Sorry for the late reply.
This video does not cover your model of carbs.
Have you looked into if OEM parts are available?
$25+
How-To: Honda CB Carburetor Clean & Rebuild
By Matthew Bochnak
I purchased this awhile back but now cannot find it. I would appreciate any help you could give me on retieval.
Email sent!
I was able to find the carb videos. Now, the recommended tools. The Auxiliary fuel tank & carb. Adjustment tool no longer seem to be available. Any alternative suggestions. This is my punishment for procrastination.
Google search Motion Pro Carburetor Adjusting Tool 08-0022
Hey, wondering if this covers the carbs for a 77/78 cb550 (keihin pd46c in my case)
No sorry it won’t cover that style of carbs.
I need that cb400 cabarator for Honda; is it possible that I can buy it for how much?
Search ebay, FB groups, and the SOHC forum classified section.