New, Aftermarket points and condensers are not reliable. They tend to fail very fast.
Spend the extra and buy from Honda the point plate assembly if you need new points and condensers.
How did you clean the carbs??
Did you clean the emulsion tubes?
Your idle is from a lack of fuel flow through the emulsion tubes or you have a vacuum leak through old rubber intake insulators, #7 & 8.
Aftermarket insulators are known to have leaking problems.
You've given too little information to get a good answer. What exactly are you looking for and to do???
Do you have the frame numbers and model of your bike too?
The engine numbers you posted show it is a 1976 engine case number.
The 1972-1976 cb750 used the same style carbs. There were...
To say it was never installed is probably not correct but it appears to be a warrantied removal pipe. You can see the ring marks where the collar was tightened on the flange.
(I was a parts manager back in the 70s)
As to the value of it?
Being it is the number 3 pipe(which is one of the last...
The SOHC(1969-1978) are dependable if take care of and not hammered too hard. But remember, these are old bikes now and need to be babied as the cam chain rubber parts are old and brittle now and need to be replaced.
I don't know anything on the DOHC bikes to help you.
I'm sorry I don't have a lot of time today to reply in full as you ask....
You didn't state what type CB750, as in SOHC or DOHC motor....
For SOHC bikes
Have you read through the site http://honda750expert.com ???
Another great site to read on is http://forums.sohc4.net/index.php
I stopped...