Author Topic: CB750 K0 idle speed screws all the way in  (Read 660 times)

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Offline BasicPoke

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CB750 K0 idle speed screws all the way in
« on: August 26, 2018, 02:15:21 PM »
A buddy of mine has a CB750 K0 that has been out of commission for 7 years or so.  These are the carbs where a separate cable goes into a cap on top of each carb.  Slides will only insert one way, so they are not backward.  He/we have rebuilt the carbs, set valve gaps, and set points gap and static timing.  I believe compression is good but I do not have those numbers.  We are currently trying to sync the carbs as best as possible without the manometer method.  Mixture screws set as suggested.  With the idle screws all the way in, we have a gap under the slides of about 1/16".  It will not idle like this.  All pipes get hot.  Air box is off.

FYI in case it matters, we have had trouble with #2 not getting hot when air box is on, but not when it is off.  We had the head rebuilt and replaced the rings about 25 years ago.  It ran pretty good back then.

1. With idle screws all the way in, does a gap of 1/16" under the slides sound normal?
2. Any thoughts about why it won't idle with screws all the way in?  We are puzzled.
Thanks

Offline Don R

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Re: CB750 K0 idle speed screws all the way in
« Reply #1 on: August 26, 2018, 02:44:58 PM »
 The slides will go in backwards if you reverse them 1-2-3-4/4-3-2-1. Ask me how I know.
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Offline BasicPoke

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Re: CB750 K0 idle speed screws all the way in
« Reply #2 on: August 26, 2018, 03:05:19 PM »
The slides will go in backwards if you reverse them 1-2-3-4/4-3-2-1. Ask me how I know.
Ok wow.  Does the cut-out go toward the airbox or engine?

Offline Bodi

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Re: CB750 K0 idle speed screws all the way in
« Reply #3 on: August 26, 2018, 03:31:05 PM »
airbox.

Offline BasicPoke

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Re: CB750 K0 idle speed screws all the way in
« Reply #4 on: September 03, 2018, 07:29:08 PM »
The slides will go in backwards if you reverse them 1-2-3-4/4-3-2-1. Ask me how I know.
This was the problem.  My buddy was concerned about this and I told him to forget about it because they only go in one way, right?  So we owe you some beers.  It is running pretty good now.  Thanks so much Don R.
Ron