Topic: 1981 CB650 Custom fuel leak/stuck float?

[FrenchShowerBag]

Hi all,

I just purchased a 1981 CB650 custom after getting my license earlier this month. It seems to have a stuck float. I left the petcock on and noticed fuel dripping out of the drain tube at the bottom of the bike (not what’s in the second photo).

When I went for a ride after this cylinder 1 (first on the left when sitting on the bike) was cold while the others were hot after warming the engine up. I smacked the carb a few times and it seemed to fix the issue so I went for a ride.

After an hour of riding the engine felt like it was bogging down so I headed home. When I got home and put the bike in neutral and let it idle the engine stalled out and it started leaking fuel again. So I’m thinking it’s the float getting stuck.

Any advice or tips on how to fix it? Is it possible to remove the float blow and spray in some cleaner? I’m new to carburetors so just looking for some advice before I potentially wreck something.

Thanks in advance!

[fizzlebottom]

A stuck float is definitely a good place to have a first look. In general, you'll be taking the carbs off and giving them a good cleaning. You'll also inspect the floats for cracks and float needles for any wear or damage.

More specifically, taking the carbs off of an 81-82 CB650 can be a bit of a bear until you get familiar with the whole process.

The first thing you'll need is a shop manual, often called a factory service manual. If it isn't listed in the Manuals & Technical Documents section of this sub, then grab a physical copy from Clymer or sit on eBay for one of the original Honda prints.

The second thing you'll need is a #2 JIS screwdriver. This is because the screws all around the carbs look like phillips screws, but they aren't. Using a regular phillips driver will wreck them and make your life miserable. Vessel is the most commonly recommended manufacturer for a good JIS driver.

Lastly, I highly suggest not purchasing any parts until you know what needs to be purchased. There are many carb rebuild kits, and many of them have terrible parts. Always avoid aftermarket jets and floats. Float needles are mostly OK, and bowl gaskets are fine as long as they aren't torn. You will likely need new bowl gaskets, but wait to order until you know if any other parts are needed. I will always suggest replacing the carb boots / insulators because they are usually rock hard and make reinstalling carbs SO MUCH easier if you have new rubber.

Worst case is that you'll need to replace one or more floats and/or one or more float needles in addition to a full cleaning. Get the manual & your JIS driver, follow the steps to remove the carbs, and get them on a workbench. Follow the manual, spray carb cleaner in every single hole you can find.

You'll find that your carbs (VB44A) have press-in slow jets, which makes some people pull their hair out. You can either leave them and try to clean or drill them out & replace with screw-in slow jets. Search YT for some info around this.

Let us know if you have more questions. I've been around these carbs too much, so I'll give whatever help you need.