carb hookup

[bikerphil]

upper vent tubes

If you have the stock airbox, they hook up there, one on each side of the crankcase breather hose. If you are running pod filters, they can remain open. Just don't cap 'em off.

[theduke]

that was my assumption, but the two posts on either side of the airbox are solid, not open. could i simply drill through them to create an opening?

[randy]

Yes, you can. Did it on mine, had swapped on a later air box and the nipples were plugged.

[DGXSER]

You seem to have an airbox off of a newer model, 80 or 81 that did not have the vents. I have not seen the inside of the ones with the vent connections so I don't know what is or is not missing on your airbox.

If it were my bike, I would probably just throw a fuel line nipple on it with a small fuel filter like I have seen posted recently. Or maybe it was just an old thread I was recently viewing.

Like Phil said, they need to be open to atmosphere to let the air out of your float bowls so fuel can come in. I suspect they ran them to the air box to recapture the small amount of fuel vapor that might escape with the air. I seriously doubt it is enough to be concerned about.

[Ivan]

I have an older airbox, and the nipples are the same, but they do have some brass tubing through the hole. Dunno if it is factory or a PO that put it in there.

[bikerphil]

78-79 airbox

I have an older airbox, and the nipples are the same, but they do have some brass tubing through the hole. Dunno if it is factory or a PO that put it in there.

The 78-79 airboxes, the ones meant to be run with the BS34 II carbs (early type) have the brass tubes (stock) in the vent hookups, probably to limit the vent airflow, so not to suck too much air thru the vent tubes.

[thewiz]

Now that bike ...

looks great!!

[screamin deal]

vents

The two lines that came off of the tee's went to the air box. I now have them covered with a small breather filter.

[Radiation]

Popping on deceleration

I had the same problems with my bike. I put new MAC exhaust on and noticed a popping on deceleration. Turns out that I had a leak in one of my carb boots that mount the carbs to the heads. I replaced them from Partsnmore and now the popping is gone and it runs like a striped a** ape! I followed the tips from this awesome site and did the spray test to find the leak.

[HiGuy]

Yaahoooo The old girl fired right up and sounded pretty darn good. I still have a few minor details like breather filters and my gasket on my oil filter cover did not seat correctly so it is leaking. I had intended on just idling for a while and changing the oil again as a flush because the oil I changed out was the gassy stuff. So now I have to anyway. When she runs with no leaks I am going to take it to my mechanic and have him sync the carbs then I should be ready to roll the next time the streets are dry.

Thank all of you for all your help and advice.

Just wondering what you meant by the "gassy stuff" since I have very gassy oil and am not sure how to stop it. I just purchased some carb kits and am thinking about rebuilding them but then got nervous when people said that they had problems after with leaking and sticking and stuff. Thanks

[DGXSER]

Your gassy already......

and Tums wont help. Sounds to me like you already have float valve problems. The gas will dilute your oil and be BAD for your bearings and seals. You should fix the carbs and replace the oil before you run the bike.

When the float valves in these carbs stick open, the fuel will fill the bowl and up through the jets into the venturi section and flow out into the air box (if you still have one) or pod filters, and into your cylinders through the open valves, or may seap through, and then seap past the rings, and into your oil. If you smell gas in your oil, chances are VERY good this is the cause.

So it sounds like you already have the problem you fear creating. Is there a chance you will have problems after rebuilding? Yes, but there are so many folks here at XS11 that are more than happy to help, you should do just fine. I had plentyof problems after rebuilding mine, but still would recommend it in your case. Only solution is for someone to do it, and you probably work MUCH cheaper than the local shop (on your bike anyway).