Author Topic: Ultrasonic cleaning carbs carburettor tips? CB400F  (Read 257 times)

Offline zombie365

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Ultrasonic cleaning carbs carburettor tips? CB400F
« on: March 21, 2021, 12:11:47 AM »
Hi All,

My 400/4 is pretty much striped down now, time to refurb some parts!

I have access to an ultrasonic cleaner and wanted to clean up the carbs, mainly just for aesthetics, engine was running sweet as a nut before strip down, so I believe the carbs are working as they should.

I've not worked on carbs before so I thought id ask somebody first...

Can I just "chuck" the carbs as a whole in the tank and turn it on? or do I need to dismantle anything before?

It has pod air filters which will obviously be removed.

Hope I don't get to much stick for my noob question!  Ha! :D

Cheers

Sam

1977 Honda CB400F

Offline gtmdriver

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Re: Ultrasonic cleaning carbs carburettor tips? CB400F
« Reply #1 on: March 21, 2021, 07:33:32 AM »
I usually dismantle the carbs but leave the bodies attached to each other as a single unit.

Offline orcadian

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Re: Ultrasonic cleaning carbs carburettor tips? CB400F
« Reply #2 on: March 21, 2021, 08:55:04 AM »
Hi Sam,
Welcome to the mad world.  No stick given on this forum for any question from someone willing to learn!  We were all newbies once and everyday is a school day for all of us.
Depending on how bad a set of carbs is, the bare minimum for me is float bowls off, floats and jets out, ultrasonic bath and reassemble and bench sync - BUT! there are seals between carbs which might not have leaked before but could be 40+ years old.

This US guy Rick has an excellent write up of the whole job and you can do less or even more if you wish.

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


Ian

Online Macabethiele (Ted)

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Re: Ultrasonic cleaning carbs carburettor tips? CB400F
« Reply #3 on: March 21, 2021, 11:29:46 AM »
I had some trepidation when I stripped down & rebulit my carbs - I found U tube videos a useful reference source but can't find a link to the one I used.
My BiL did the ultrasonic bit of the carb bodies after I had stripped them down.
Looking back at an old thread I did make some basic errors when re-assembling but it was sorted here!
Turned out a stripped thread was nothing of the sort I was just trying to put it back together all wrong.

This video helped me.


https://www.youtube.com/watch?v=JFTOfYl5BSc
« Last Edit: March 21, 2021, 11:33:18 AM by Macabethiele (Ted) »
Honda CB400F2 under restoration
Jeep Grand Cherokee WJ
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Offline element137

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Re: Ultrasonic cleaning carbs carburettor tips? CB400F
« Reply #4 on: March 31, 2021, 08:48:46 AM »
I stripped the carbs completely - following the same  link posted above from orcadian  http://www.vintagebikebuilder.com/cb350-400f-carb-rebuild-demonstration.html - really easy to follow guide - I had never stripped carbs before and to be honest was really daunted by it - in the end - really enjoyed learning how to do it -
I purchased a small 3 litre ultrasonic machine that I used for all the small brass components - and put a liquid dishwasher tab in the water as a detergent/cleaner - worked really well at 30mins cleaning -   then the bodies, caps, float bowls I used a big industrial size ultrasonic machine at work - although just a warning - it turned the bodies a darker grey as a result of the process, I then had them professionally vapour blasted and they came up like new - I also had to rebuild a couple of times as I couldn't get the aftermarket float valves to seal properly resulting in leaking carbs - once re-fitted (cleaned) OEM parts all OK- good luck with it - 

 

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