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Yes they are drilled out . As far as leaking I am tracking down all of the fuel leaks and I am thinking the right one is . My right boot gets damp with fuel and the left side of the motor / trans gets a good cleaning every time a took the bike out . I did find out that number 3 and 4 carbs has developed bowl seal leaks but I noticed that 1 and 4 had the out sided wholes . There has been a lot of hands into this bike over it 30 years life and I am thinking these are not the the carbs that the bike came with from the factory .

Mike

 

Do your carbs have overflow lines? Do you have a vacuum operated fuel shutoff valve at the tank? Some early bikes had overflow lines and when the carb needles got trash under them and leaked, the carbs would fill to the overflow and gas would run on the floor. That is the way my 81 CB900C is. My 2004 Concours does not have overflow lines for emission reasons I suspect. It also has a vacuum operated diaphragm fuel shutoff valve. Many Concours owners have had the diaphragm fail in the fuel supply valve and then the needles in one or more carbs start leaking while the engine is off resulting in hydrolock and destruction of the engine when the operator tries to start it the next time.

 

RoadRunner It does have a vacuum petcock . I did pick up some fuel that had a lot of trash in it . I have to replace the inline filter that I put on it in March . Between the fuel leek and the filter being almost plugged It would run for a while and then shut down . If you did get her going it would run week then shut down . I looked this afternoon and notice that there is left over glue around the wholes . I am thinking of using a small screw to block off the wholes and after I replace the bowl seals and the drain O rings I am going to try it out and if everything works then use a lite coat of epoxy around the screw heads just to keep them in place .
If I see any fuel on the floor I find out why and I do not try to start until I find out . I park my bike on card board in my garage so I can see in anything leaks . The bike is 30 years old so I like to keep an eye on it .

Mike

 

Those in-line filters in the fuel line are nice to have but even clean they restrict fuel flow enough that the engine usually starves for fuel at high rpm. I installed one on my ZN700 as soon as I bought it and that is when I found out. Most tanks have a screen on the inside of the tank that is part of the fuel valve that helps. Probably should kreem the tank and just use the screen.

 

I had the screen out in my tank and the only thing it is going to stop is a frozen 20 pound turkey . I put an auto inline filter in . I thought if it has inof flow for a 350 V8 then it should be OK for my little 4 cylinder . I have already cleaned the tank out and filtered all the trash . I will run the fuel in my old lawn mower . It eats anything .


Mike

 

If it is a large filter you may be correct. However, there is a big difference. Cars have fuel pumps pumping the gasoline. Your bike only has less than one foot of head pressure which equals less than 1/2 psi.

 

The one I use is a large filter .

 

All four of my carbs leak from those nipples or whatever they are on the bottom of the carbuerators. They are on the top in the above upside down picture. They leak a lot. What the hell are those nipples and how can I make it stop?

 

:shock: the nipples are vents or overflow tubes for the gasoline in the carbs.

 

Why do they leak a lot of gas and stuff then?

 

I put some hoses on it directing it to the ground, my daily driver can't afford to have it down.

 

The nipples at the bottom of the carb bowls are the overflow ports. If fuel is leaking, there may be a problem with the float needle valves & seats: either there's debris keeping the valve tips from seating or they are worn/defective. Another cause for fuel leaks there is from a defective petcock or a petcock left in PRI while parked.

 

The peacock has been reserve apparently this whole time too but I switched it to on. Haven't noticed a difference between reserve and on, I don't even see the point in reserve... What are float needle valves/seats? I come from the land of fuel injected cars and trucks.

 

ON is the normal setting & RES is the reserve (ie, reserve fuel supply): when the fuel in the tank gets low, you should switch the petcock to RES, then find a gasoline station. On my 81 650 after the bike starts to sputter & after switching to RES I can travel approx. 20 miles on the reserve amount of fuel left in the tank. If the petcock screen is missing, then there is no RES --- the screen has a pickup tube that is an inch or two higher than the bottom of the tank.

Carburetors have a mechanical system for regulating the amount of fuel in the carb bowls.
Search youtube for how a carburetor float works or something like that.
In this video the float & needle valve are in the lower right. youtube --- CV Carburetor
If crud gets between the needle valve tip & the seat, the carb will leak when parked.