Honda CB400F2 setting the float levels.

[McCabe-Thiele (Ted)]

Okay so even though I have new float seats & valves plus the new floats, I guess I need to check the actual float levels.

Is there a basic measurement that I can take to set them all the same presumably without the bowl fitted?

If this information is already on the site can someone point me to the right post please?

Likewise what's the best way to set the main slides are all the same is it as I have seen on U Tube to use a 1/8 drill shank?

Thanks

[Nurse Julie]

Here's Bryan excellent fool proof method to bench cync carbs
http://www.sohc.co.uk/index.php/topic,17769.0.html

Later, I will post some photos of setting float heights.

[SeanFD]

The recommended float height is 21mm.

I have just done mine and it is - at least I found it – next to impossible to get them all at the exact height and even on both sides. In the end I settled for between 20.53 and 21.55 across all 8 measurements (2 per float).

Good luck.

[McCabe-Thiele (Ted)]

The recommended float height is 21mm.

I have just done mine and it is - at least I found it – next to impossible to get them all at the exact height and even on both sides. In the end I settled for between 20.53 and 21.55 across all 8 measurements (2 per float).

Good luck.

Okay I've seen that figure quoted elsewhere but how do you measure that 21 mm from where to where?

Sorry if my question is very basic - to me a float level should reflect the depth of the fuel in the bowl when the float has cut off the fuel supply by shutting the needle valve - this would then ensure the right fuel pressure to the main jet for the correct mixture etc.

Presumably someone has translated that into a measurement taken when the carburetor is inverted without the bowl fitted so the needle valve is shut. As the float is in two halves I can see why the correct measurement is difficult.

When I have worked on older cars the workshop manual would often quote a gap at the top of the float arm to the upper body usually dead parallel with the needle valve closed.

Is the 21 mm measured between top part of the Carb body & the steel part of the float assembly??

[Nurse Julie]

The recommended float height is 21mm.

I have just done mine and it is - at least I found it – next to impossible to get them all at the exact height and even on both sides. In the end I settled for between 20.53 and 21.55 across all 8 measurements (2 per float).

Good luck.

I'm sure that will be close enough, it just shows the brass float arms were very slightly bent if you are getting different measurements on both floats. I'm in the process of doing a 'hints and tips' on carb float settings at the moment, with some photos, I'll try and get it finished later today and post it on here.

[Nurse Julie]

The recommended float height is 21mm.

I have just done mine and it is - at least I found it – next to impossible to get them all at the exact height and even on both sides. In the end I settled for between 20.53 and 21.55 across all 8 measurements (2 per float).

Good luck.

Okay I've seen that figure quoted elsewhere but how do you measure that 21 mm from where to where?

Sorry if my question is very basic - to me a float level should reflect the depth of the fuel in the bowl when the float has cut off the fuel supply by shutting the needle valve - this would then ensure the right fuel pressure to the main jet for the correct mixture etc.

Presumably someone has translated that into a measurement taken when the carburetor is inverted without the bowl fitted so the needle valve is shut. As the float is in two halves I can see why the correct measurement is difficult.

When I have worked on older cars the workshop manual would often quote a gap at the top of the float arm to the upper body usually dead parallel with the needle valve closed.

Is the 21 mm measured between top part of the Carb body & the steel part of the float assembly??

We crossed post there, see my reply abive 😊😊😊

[McCabe-Thiele (Ted)]

Here's Bryan excellent fool proof method to bench cync carbs
http://www.sohc.co.uk/index.php/topic,17769.0.html

Later, I will post some photos of setting float heights.

Yes that seems a pretty good way for setting the throttle stop screws thanks for that - I look forward to photos on float heights. Thanks NJ.
I've seen your post in the Tips section first one took me ages then it was much easier - all four done now.