Re: carb rebuild issues

Posted by seestheday on Jun 05, 2013; 12:41am
URL: http://vintage-and-classic-hondas.81.s1.nabble.com/carb-rebuild-issues-tp4041611p4041809.html

Damn, this really sounds like it is a vacuum leak.

Are you sure that those are the right slow jets?  According to this site you should have #35's in there:
http://www.siriusconinc.com/pro-detail.php?pid=&product_id=3788

Here is another reference to them being #35: http://cb750c.com/modules.php?name=Forums&file=viewtopic&t=11661&highlight=slow+jet+size

My slow jets are pressed in so I've never taken them out, and I don't see them listed in the manual, but 72 sounds huge for a slow jet.

What is the number on the side of your carbs?  Are they VB42A?  VB42B?

It is also possible for these carbs to have vacuum leaks around the body of the carbs (e.g. at the throttle linkage).  Checking there with a flamable aerosol would be prudent.

Some other stuff it might be...

Did you remove the SOS, and if you did, is your vacuum nipple sealed off tight?  It's in between carbs 2-3 on the head side of the carbs.

You say under the caps is all good.  Did you verify that that slides rise and fall smoothly like in this video?