Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: XS850 on November 25, 2025, 12:38:47 PM

Title: Float Heights (again!)
Post by: XS850 on November 25, 2025, 12:38:47 PM: Hi All, can someone supply the relevant photos from Nurse Julie’s float height set up please, they’re not appearing when I go to the relevant tips & tricks post!

Also - has anyone ever measured the fuel quantity of a correctly set up float height? I’m getting 40ml on each carb - does that sound about right for CB400F float height setting?

Many thanks - Bruce
Title: Re: Float Heights (again!)
Post by: Nurse Julie on November 25, 2025, 01:49:33 PM: [attachimg=1]

[attachimg=2]
Title: Re: Float Heights (again!)
Post by: McCabe-Thiele (Ted) on November 25, 2025, 03:29:18 PM: I found these two links handy for setting the 21 mm float height, its quite a way down on the Vintage Bike builder, likewise it links you to the second site that wil show the 400 float type.

www.vintagebikebuilder.com/cb350-400f-carb-rebuild-demonstration.html

www.vintagebikebuilder.com/setting-mikuni-float-levels.html

I bought an inexpensive poor quality float gauge, I ened up using rubber bands to hold the setting in place. Mine was about £6 the one below looks a tad better

www.ebay.co.uk/itm/205068441561
Title: Re: Float Heights (again!)
Post by: Athame57 on November 25, 2025, 03:42:54 PM: I use a gauge like this to set float heights myself. ;)
Title: Re: Float Heights (again!)
Post by: exvalvesetdabbler on November 25, 2025, 03:50:02 PM: Use. A Vernier caliper with depth gauge if nothing else.
Title: Re: Float Heights (again!)
Post by: McCabe-Thiele (Ted) on November 25, 2025, 04:52:30 PM: IIRC Ash made one out of an early PC floppy disc case!
Title: Re: Float Heights (again!)
Post by: Laverda Dave on November 25, 2025, 10:21:59 PM: You can make one from an old credit card (or even a new credit card to save unwanted spending on Christmas presents 🎁) 😉
Title: Re: Float Heights (again!)
Post by: XS850 on November 26, 2025, 08:57:51 AM: Thanks Nurse Julie - exactly what I was lookin for that makes more sense to me with your description!

Also thanks to all other comments - I have a float height guage, it was just the description of what angle to have the carbs at for setting the “close” position!

Cheers - Bruce
Title: Re: Float Heights (again!)
Post by: Bryanj on November 26, 2025, 02:48:40 PM: One question looking at julies pics is are the floats the right way up?
Title: Re: Float Heights (again!)
Post by: Nurse Julie on November 26, 2025, 04:33:24 PM: Quote from: Bryanj on November 26, 2025, 02:48:40 PM
One question looking at julies pics is are the floats the right way up?

They were probably 500 or 550 carbs that I was fettling Bryan but I just took the photos as an example of how to set the floats.
Title: Re: Float Heights (again!)
Post by: Bryanj on November 26, 2025, 05:58:38 PM: Just a query as i just rebuilt a set for Paul Whitely and i think they came out other way up so you measured to flat side