Topic: 1983 cb1000 custom

[chadwick70]

I know this is a little off topic, not being a sohc...but here goes. I'm trying to get this bike running smooth and it's just not happening. There are a couple of tubes coming off the carbs that just dont connect to anything, and when the bike starts its REALLY rough and has virtually no power. It has electronic ignition, and the smog crap on it, one of the tubes may be a vacuum line but WHERE DOES IT GO??? Help guys...I'm pullin my hair out!!!

[MRieck]

That bike has a vacuum operated petcock. One of the lines attches to a small brass tube on carb # 3(if I remember correctly. The other line is simply a vent goes over the and around the back of the airbox (there are some little tabs on the top right side of the airbox). If the vacuum line is not attched to the carb you have a huge vaccum leak which causes the rough running. Also keep in mind that you will have to prime the carbs (get fuel in the bowls) after you remount them. That can be accomplished by applying vacuum to the same line for a minute or so.

[chadwick70]

Yeah...the two tubes you see hanging there...the one on the left is attached to the brass nipple on #3...the other one just hangs there? So my question is...the one attached to # 3 carb goes where? There's only one nipple on the petcock and thats for the fuel line. I don't see a vacuum nipple...

[cb650]

That "thing" there between 1 & 2 is the vacuum fuel shutoff.   The other end of the line should go to the carb.  Its on top by where the head would be.  The other carbs have little brass screws in them at this location.  Do yourself a favor and get rid of it and plug that carb up too.  Just jet into the habit of shutting gas off.


                 
                              Terry

[MRieck]

Yeah...the two tubes you see hanging there...the one on the left is attached to the brass nipple on #3...the other one just hangs there? So my question is...the one attached to # 3 carb goes where? There's only one nipple on the petcock and thats for the fuel line. I don't see a vacuum nipple...

There has to be a vacuum nipple to move the diaphragm so gas can flow. It's so long since I've touched one of those I can remember where it is. Are you sure the long vent tube is where it should be?