I pulled my carbs today and found that the air cut off valve was broken off where the vacuum tube connects to it. Ive been in the process of diagnosing a problem, and I am curious what the symptoms of a broken air cut off valve would have been.

Thanks,
Phill

 

There are 3 hoses attached to the Air Cut valve. It would depend on which one was affected. Item 18 on the left is the normal one. California models have 2 of them, shown to the right. PAIR Valve

 

Sorry I didnt elaborate better I was writing from my phone at work. This is what im referring to-




The cut off valve was broken off where i circled, so the vacuum tube was not attached to the valve itself. This is on the right side of the carburetor block, next to the #4 carb. Sorry for the bad picture out of the manual, ill try to take a better picture tomorrow morning.

 

Little bit better detail- The vacuum tube goes from that bottom fitting and into the valve. The tube broke off at the top circle.

http://fiche.ronayers.com/Index.cfm/...TOR_COMPONENTS
#28- New OEM for this part is around $55...not cool

 

Might have answered my own question- was reading through an old CH250 site where the author was diagnosing deceleration backfiring and read this-

6. Air Cut-off Valve. This component is the prime suspect. On the back of the CV carb is the air cut-off valve. The air cut off valve enrichens the pilot circuit on deceleration by means of a rubberized piston. One hose to the valve (nearest air filter) is the air tube connector and the other (nearest the autobystarter) is the vacuum connector port. If air pushed through the cut-off valve by a pressure pump leaks by the vacuum port connector while vacuum is initiated with a vacuum pump, replace the air valve. I replaced a faulty air cut off piston and my backfiring ceased. The air cut-off valve is expensive (about $70) and should be replaced after all other suspects tested have failed.

I was actually in the process of diagnosing a lean mixture/exhaust deceleration popping, and it sounds like this may have been the cause of it. The guy was writing about a moped carb, but they are both CV so im assuming both have similar components. Does this sound right?

 

Yes, absolutely. Right on the mark. I believe there are 2 of them on the carbs.

 

Thanks again Dirt. I ordered a new cut-off valve and vacuum hose through my local Honda dealer, should be here on Friday. Ill post an update hopefully this weekend. Cant help but feel like ive got a gremlin in my carburetors this season lol

 

when jetting my bike, I had to insert 2 "stoppers" which plugged both of those tubes.
Didn't change the way my bike ran though

 

Accidentally deleted my last post, but everythings working great now. No more popping while decelerating, and overall shes running alot better.