Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Gary400/4 on July 07, 2021, 07:36:50 PM
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I have taken my cb400/4 carburettors off a number of times to fully overhaul them. I have just replaced the main jets,emulsion tubes, throttle needle, set on third groove. Float needle valve and seats. Running a standard airbox, Throttle slides set at 1 mm at wide open throttle, seen from air intake side. The push cable distance set at 56mm, The carb kit I've purchased is from Red brain Honda eBay shop. I haven't got any obvious air leaks, my carb rubber intakes are not split and securely clamped, as well as the air filter ones.I have used the Haynes CB550 400/4 for reference data. To set the carbs. I am starting to suspect the information I am reading. Is there any Honda technical data.
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Can you close the slides completely?
Then use the tickover adjuster to lift them to the correct speed
Sent from my SM-A750FN using Tapatalk
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If you have replaced all the brass ware with aftermarket parts, put the original bits back in if they are OEM. As John said, the slides should be closed fully with the main idle adjuster backed of fully.
Edit... Also check the distance on the fast idle function which the 400 has.
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Adding to the above advice, with cables disconnected can you fully close the slides with the idle speed adjustment "master" screw?
If not, they may have been set such that you can't get them to shut off enough to give competent throttle closing.
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Many thanks guys, (I've been at my wit's end over this).For giving me a pointer to work with, the thought did occur to me to fully close the slides and adjust with the throttle tickover screw. But I decided that the manual must be correct and doesn't mention fully closing the slides. Only setting then at wide open throttle. The carb kit came with 35 pilot jets as opposed to the OEM 40 pilot jets. I have retained these in the carbs.The float valve needles are better as the springs are stronger to deflect the floats. When setting the 21mm height.
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What manual are you using?
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What manual are you using?
Think he mentioned the Haynes manual.
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Then burn it and read the bench sync in tricks and tips
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Thanks folks, yes it was my much thumbed tattered Haynes manual, I got my carburettor set up data from. If anyone knows of information more appropriate to setting up the carbs I would appreciate to receive it
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Thanks folks, yes it was my much thumbed tattered Haynes manual, I got my carburettor set up data from. If anyone knows of information more appropriate to setting up the carbs I would appreciate to receive it
As Bryan said above, look in Tricks and Tips on here for the Bench Sync guide.
It's on Page 2, Basic Bench Carb Balance
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http://www.sohc.co.uk/index.php/topic,17769.0.html
Follow carefully as some of the steps may seem insignificant but are vital in directing you to a fault free setup.
It will produce a final setup that gives correct operation and mechanical balance without any other "tuning" needed to run them correctly.