Part identification

[phenrichs78]

Can someone help me identify the part circled in the photo? I have a place on my carbs where it is obvious something was mounted but no part in my box. I found a photo that shows this part bolted where I have something missing but I have no idea what it is.

 

[Steve83]

That's the air cut-off valve. A vacuum hose runs from the nipple on it to the one on the float bowl on the same carb.

 

[phenrichs78]

Thanks now I can search for one.

 

[Dusterdude]

Sorry to hijack,but what does that do?thanks

 

[Steve83]

Someone who knows please correct me if I'm wrong, but I believe the cut-off valve restricts gas flow during high manifold vacuum - deceleration - to prevent backfiring.

 

[Dusterdude]

Thanks steve

 

[ekvh]

I'm probably wrong, but I am thinking it is the opposite, to add fuel to the lean condition caused when you cut the throttle causing backfires. I read that racers would seal them up totally as the backfiring didn't bother them.

gallery/image_page.php?album_id=1125&image_id=11233

 

[dan filipi]

The same is true on the 1100's except that each carb has one.

 

[roncar]

Actually it cuts off the air (ie air cutoff valve) to increase the fuel in the mixture during deceleration due to the lean idle mixture when carbs are set up per OEM specs.

Some interesting info here. https://www.motorcycleproject.com/motorc ... _more.html

And here. https://www.motorcycleproject.com/motorc ... _paper.swf

 

[joedrum]

that some good stuff ron