Author Topic: 400/4 float heights  (Read 301 times)

Offline alfiembra

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400/4 float heights
« on: May 25, 2022, 03:33:58 PM »
I’ve recently overhauled my 77 400/4 carbs with a kit from the USA, from 4into1.com had the kit for many years but never fitted it. Now that I’ve done it the float height is concerning me slightly, the bottom of the floats do not sit parallel to the face of the float bowls but neither did the originals before I took them apart. When I measure from the face of the bowl to the lowest point of the float it measures 21mm which is what I understand it should be, but at the high end of the float it measures 23/24mm. Should the float be a constant 21mm straight across or does this sound right?

Also any tips on setting them up statically before refitting them.

Thanks in advance.

Offline Nurse Julie

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Re: 400/4 float heights
« Reply #1 on: May 25, 2022, 04:08:35 PM »
Set as per following at 21mm for a 400/4
http://www.sohc.co.uk/index.php/topic,23233.0.html
« Last Edit: May 25, 2022, 04:10:41 PM by Nurse Julie »
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline Nurse Julie

  • 1973 CB750 UK K2.1977 CB550/4 Mongrel Brat. 1974 UK 500/4 K1
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Re: 400/4 float heights
« Reply #2 on: May 25, 2022, 04:16:35 PM »
And here is Bryan's tutorial on how to bench sync prior to fitting.
http://www.sohc.co.uk/index.php/topic,17769.0.html
Im a Nurse, trust me, this won't hurt.....much !!!

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

Offline alfiembra

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Re: 400/4 float heights
« Reply #3 on: May 25, 2022, 11:30:04 PM »
Thanks Julie I’ll set the floats up using your guide. I’m not sure I follow Bryan’s guide for setting the slides will need to have another read on that. If I’m understanding it correctly after undoing the tick over screw you set the lowest slide with the drill bit shank as a feeler gauge, do you adjust that slide with the slide adjuster then set the idle screw to that position? Then adjust the rest to match. The way I read it you set the slide height with the idle screw and then adjusted the rest with the slide adjusters. Probably my bad. Thanks again.

Offline Sesman

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Re: 400/4 float heights
« Reply #4 on: May 26, 2022, 07:10:53 AM »
Correct. Set the first slide till it’s just touching with the slide adjuster, then use the idle screw to lift it 1/16th. Set the remaining slides using the slide adjusters without touching the idle screw.

Offline Bryanj

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Re: 400/4 float heights
« Reply #5 on: May 26, 2022, 08:28:46 AM »
The point is that slides need to be able to touch the base thus totaly closed to start, then use big adjuster till one is open enough to use the drill bit as a feeler, smallest available 1/16 max and preferably new so no damage on shank.
Then set other 3 to same and finally check that all close with big screw wound out.

 

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