Cut air valve problems

[forden34]

One of my CAV is broken with a small crack
What happen if that is broken??

[forden34]

Vake upppppppp

[icerigger]

I'm going out on a limb here and say that cylinder will probably run leaner than the rest. How much leaner depends on the size of the crack. I would either replace it or bypass the valve entirely.

[seestheday]

Do all of the different carbs have air cutoff valves?

I'm only familiar with the DOHC CV carbs and they definitely have air cutoff valves that are easily bypassed (often making the bike run better).

What year is this bike?  

[forden34]

DOHC 80-83
Cylinder nr 1 not get gas enough i think and that is ACV broken
So if i take apart the carbs agani it would work if i plug all ACV??

[seestheday]

Pics will help. Could be more damage. What caused them to crack? Lots of little tiny passageways in these carbs. If you're taking them off you might as well give them a real good clean at the same time. That would fix clogged jets at the same time. Great instructions on how to do it in the dohc carb cleaning thread. Download the manual linked to from there, it's the best resource on these carbs.

[forden34]

I have clean the carbs
I follow the instructions for clean carbs

[seestheday]

You followed the MacGregor carb cleaning manual exactly but are asking questions about blocking the air cut off valves? It explains it better than I can here...

EDIT: cleaned up the crap attached when replying via email

[forden34]

Sorry to ask, not happen again

Sorry

[forden34]

Did i say i follow that instructions?? No i did not

Is this a forum or what?

[LukeM]

Just a gentle reminder that this forum is a voluntary group. No one's getting paid for answering questions or providing information, and in fact our benefactor (Re-Run) pays money to host this site. He has not asked for any compensation for this service, despite many offering to contribute on many occasions.

Please be patient if someone doesn't update your posting as soon as you'd like. I know the warm weather is coming, and we'd all like to get our bikes in good shape, but most of us have other things in our lives that keep us pretty busy.  In the meantime, if someone hasn't followed up, go read the documentation for your situation a few times, and see if the answer presents itself.

We now return you to the question at hand.
Luke M

[seestheday]

There is a language barrier here as well, so I'm not taking offense to some of the demanding tones in his messages.  

[seestheday]

forden - here is a link to the dohc carb cleaning thread I mentioned in the previous post:
http://honda-cb750-s.456789.n3.nabble.com/DOHC-carb-cleaning-procedure-td867809.html

Reading the whole thread will be beneficial, but here is the direct link to the MacGregor carb cleaning manual:
http://www.google.com/url?sa=t&source=web&cd=1&ved=0CBoQFjAA&url=http%3A%2F%2Fwww.cb750c.com%2Fpublicdocs%2FSeanG%2FHonda_Carb_Manual_revE.pdf&rct=j&q=macgregor%20carb%20cleaning%20honda_carb_manual_revE.pdf&ei=9q2JToOwNIPegQe5wZz6Cg&usg=AFQjCNEmSmzw9aIam2qmA7UAwPZ309Y5Jg&sig2=A2e2jvA9r9A4UvfIISOENQ&cad=rja

In the thread, there are two methods outlined on how to clean the carbs.  The first doesn't involve separating  bank apart, and the MacGregor one does involve separating the bank.

The MacGregor method is more time consuming, but you end up with cleaner carbs.  The method where you don't split the bank may be enough to get you running.

Both methods go into detail on how to bypass the air cutoff valves.