I hsave a 1968 R60US with 32,ooo miles. Sometimes in starting, if I lightly depress the carb ticklers once or twice ( total of 1 sec depressed, if that) I get a stream of gas from mthe carb. I remember someone once telling me that a spring gets hung up sometimes in depressing the tickler.allowing gas to escape... Can anyone help me on this? Sometimmes a wack on the side with a wooden dowel causes the leak to stop.
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/2 carb drip
- Thread starter chwood4
- Start date
A number of things could be going on. Something is not letting the float come back up. As you said, the probe that sticks down might not be springing back. It could also be that the float is sticking due to build of corrosion. They have a thin metal shoulder around the lower edge which is supposed to help them to align in the bore of the carb. If corrosion has built up, that shoulder could be catching. Probably need to take the carb apart and clean it.
Do you have the older brass floats? Over time they will develop stress cracks...just a fact of life. They could not be floating so well if they are taking on a bit of gas. Vech at Bench Marks is marketing a new plastic float of the correct weight. I tried his Ver 1.0 of those floats and unfortunately they swelled with the ethanol. He returned my money. I understand he has Ver 2.0 out now. Might be something work considering. The brass floats can't be purchased anymore.
Do you have the older brass floats? Over time they will develop stress cracks...just a fact of life. They could not be floating so well if they are taking on a bit of gas. Vech at Bench Marks is marketing a new plastic float of the correct weight. I tried his Ver 1.0 of those floats and unfortunately they swelled with the ethanol. He returned my money. I understand he has Ver 2.0 out now. Might be something work considering. The brass floats can't be purchased anymore.
Thanks for the info, I'll take a look inside and seee what I find.....
vechbmw
New member
The brass floats are still available. (we have them in stock) But they all crack eventually. Yes, version 2 plastic floats are available and we have not had any problems with them, so far.
What you did not mention, is that there are two needle and seat/float lid versions on these carbs. If the nipple that the fuel line presses on, is in the center of the lid, you have the older style float needle type. On this type, the rod that passes through the float is the float needle, and it has a "pencil" point on it, and acts directly on the seat to cut the flow of fuel off. This type generally does not stick, and flood.
The later "lever top" float lid has the inlet nipple off center in the lid. The rod that passes through the float is not the float needle, but just a guide shaft for the float. In this type, there is supposed to be a small, thick washer just above the float on the shaft. This washer comes in contact with a hinged brass lever, that in turn pushes a rubber tipped float needle up into the seat.
The "lever top" assembly does create flooding problems some time, when the tickle plunger is used. When the tickler is depressed, it can let the lever go down far enough that the rubber tipped needle will come out of the seat enough to cock in the entrance to the seat. When this occurs, fuel will flow non stop and flood the cylinder badly. And raw gas will drip out the air mix needle. Generally, a light tap on the outside of the float chamber will dislodge the stuck needle and it will jump back up into the seat and then shut the fuel flow off. But it is too late by then, it is already badly flooded.
In reality, perhaps you should revise your starting technique. instead of your usual starting technique, try this instead. The reason being is that if you flood the engine, and ever get the spark plug wet, with fuel, just once, even though you pull the plug and dry it out, and it will fire when removed from the head That plug will not fire under compression. It is more difficult for a plug to fire under compression than it is in free atmosphere.
I've been riding and working on these bikes for 35+ years. Don't ask me why this is so, but it is. You can remove those plugs that have been wet with gas and install new plugs, and the bike will fire instantly.. Whereas you can kick your brains out with the gas fouled plugs and it will not run.
Try this starting procedure
1. have the bike on the center stand. (never on the side stand for starting)
2. turn the petcock on and count to 5 slowly, 1001, 1002 etc.
3. turn on the key
4. kick it, and LEAVE THE THROTTLE SHUT.
Assuming the carbs are set correctly, and the timing, the bike should start on one or two kicks and idle. Do NOT touch the throttle, let it idle until the engine warms up some. If you open the throttle, it will die. The reason for this is that a cold engine requires a richer mix than a hot one. The idle circuit is designed to run slightly rich. The main jet is for running on a hot engine.
The reason is, carbs are really nothing more than a variable diameter venturi with
a means of introducing fuel at the neck down of the venturi.
In order for the carb to create a vacuum to pull fuel in the velocity of the air must be high. The velocity of the air is higher with the throttle closed. You see, you cannot kick it as fast as it idles. So, when kicking the engine over, the air velocity is low. Opening the throttle while kicking makes the venturi larger, and drops the velocity of the air even more and the engine will never start, because there is insufficient vacuum to pull fuel, unless you flood it with the ticklers. Which is a bad idea because you can overdo it, and wet foul the plugs.
I have found that the procedure is a bit different when starting the engine hot.
When starting hot, do all the same things as mentioned above, but this time, have you hand on the throttle. And when you kick it, when the kick start lever hits the rubber stop on the frame, simultaneously crack the throttle open just a little. It should fire right up.
These old bikes have a personality. You must do what it wants, it is not going to do you you want, when it comes to starting.
Sincerely,
Vech
