'clear tube' fuel level check problem

[RipRoaringFun]

I went to do a fuel level check on my 1981 gs1100Ex. I have had the carbs off recently and I set the float levels to spec. However I now want to do another check of fuel level, using the clear tube-connected-to-carb-overflow outlet.

The problem is -- at the bottom of the float bowl on these carbs, there is a screw -- when I unscrew it, gas comes out. Fine. That's expected.

But there is no nipple on the bottom of the float bowl to connect a piece of clear tubing to check my fuel level.

The manual calls for using a 'fuel level guage' which in the picture just looks like a piece of clear tubing with a screw-in nipple that threads into the bottom of the float bowl. I don't have this 'guage' but I do have the tubing.

How do you folks perform this fuel level check without that 'guage', if all you have is some clear tubing? Is it possible?

 

[Agemax]

if you have set your float levels and the carbs aren't overflowing, and you have no running issues then there is no real neccessity to do the clear tube check.
as you say, the screw is a drain, the overflow is if the fuel level is to high

 

[Guest]

I found a threaded brass 'thing' that fits and I can attach a clear tube to it. No clue where it came from just found it in my box of misc. bits. Often there is someone on ebay selling the actual tool though, or something that has been made to do the job. I suppose you could make you own as well. Really all you need is a hollow tube and thread the one end to fit into the float bowl drain.

 

[Nessism]

You need to make the tool by drilling into a screw or similar and gluing or brazing a piece of tubing to it. Stick on a piece of clear tubing and you are ready to check the fuel level. This method to adjust the fuel height is much more accurate than using the float measurement alone. I suggest setting up your carbs on the work bench and filling them with fuel there because it's a pain measure the fuel level on the bike and then have to take the carbs off several times.

Good luck.

 

[RipRoaringFun]

You need to make the tool by drilling into a screw or similar and gluing or brazing a piece of tubing to it. Stick on a piece of clear tubing and you are ready to check the fuel level. This method to adjust the fuel height is much more accurate than using the float measurement alone. I suggest setting up your carbs on the work bench and filling them with fuel there because it's a pain measure the fuel level on the bike and then have to take the carbs off several times.

Good luck.

Excellent advice, I put only so much faith in my ability to set the float height by measurement. I already set the float height by measuring, but that is not exactly the ambient condition of the carb. The clear tube is the actual, 'float-bowl-full-of-gas' condition that is as close as is possible to the real running condition. If you have doubts about the level, which at this point I do, imo nothing beats checking with gas in the bowl.

 

[Tom R]

I'm almost embarrassed to post this; but this is how I did it. That's 5 mm between the pieces of tape and, yes, that is an old grease fitting I drilled out. For the tubing that clamps AROUND the bung on the bottom of the bowl, I think it was 3/8" vinyl tubing that I heated and melted around an allen bolt similar to the size of the bung. Then I clamped it to my grease fitting and ta da!

Probably took an hour to make; but most of that was rooting around boxes of stuff looking for the directions.

I clamped it on and checked mine with the bike running - I had some sort of a gutter system (aka piece of plastic) to drain the bowls into a gas can - and for the first time had a fire extinguisher on the ready.

As it turns out all my float levels were high. I'm sure that's because I bench set them before I knew that the spring on the float needle shouldn't be under the weight of the float when you measure the height. There was a fair bit of variation between how far off they were, though. Maybe it runs better - it's hard to say.

 

[Sandy]

Actually, making something that will work is far easier than you would expect. Recently when troubleshooting a minor carb issue I wanted to check the floats with the carbs in place and simply took a piece of that fairly thick wall, small ID clear gas line, cut a 5" - 6" piece, shaved one end into a taper, stuck it in the drain hole (VM Carbs), gave it about 1/2 - 3/4 turn and voila it worked and didn't leak.

 

[Steve]

I'm almost embarrassed to post this; but this is how I did it. ...

There NOTHING to be embarrassed about there, Tom.

Might not be the "prettiest", but I would certainly call it an "elegant" solution to the problem. :clap: :clap:

.

 

[MisterCinders]

Z1 sells a float level gauge for less than $10.

http://www.z1enterprises.com/detail.aspx?ID=4160

HTH

 

[RipRoaringFun]

Okay excellent, Tom and Sandy, since I cant wait for Z1 to ship me that cool tool after Jan 1 (thanks MC for that, good to know that Z1 sells one) I'm gonna fabricate one so I can run the test tomorrow/Saturday.

By the way I sprayed Engine Starter spray all over the intake tract, on the intake manifolds, the carbs, the boots between the rear of the carbs and the airbox and so on. NO LEAKS. My engine revs did not pick up at ALL so there is no intake leak.

So I'm hoping that my fuel level check will explain why cylinders #1 and #2 are so damnably lean. Cylinders #3 and #4 are perfect.

If I find that the fuel levels are fine in carbs #1 and #2, I found something that might explain how #1 and #2 cylinders are lean but #3 and #4 cylinders are fine. I would appreciate some feedback on this.........

.........there is only one gas hose that leads from the gas tank petcock to a 'T' connection between the #2 carb and the #3 carb. The fuel flows down from the petcock into this 'T' and part of the gas goes into carb #2 (and carb #1 too I assume), and the other side of the 'T' supplies gas to carbs #3 and #4.

So I'm wondering -- if there is a partial blockage on the left side of the 'T' maybe the flow rate of gas into carb #2 (and hence carb #1 as well) maybe the rate of flow of gas into #1 and #2 is slow due to a *partial* blockage.

In other words, when the bike is sitting, there's plenty of time for gas to fill float bowls #1 and #2 but when the bike's running, maybe a partly-blocked 'T' is under-supplying carbs #1 and #2 but carbs #3 and #4 on the other side of the 'T' are getting correct fuel flow and that's why cylinders 3 and 4 are running great.

I noticed this and thought 'okay here is something on the bike that divides carbs 1 and 2 in one group and carbs 3 and 4 in another -- a 'T' that divides gas flow, half into carbs 1 and 2, and half into carbs 3 and 4.

This 'T' being partly clogged on one side could explain why 1 and 2 are under-supplied with gas but 3 and 4 get the right amount.

Anyone ever seen a clogged fuel 'T' on these bikes? Could a 'T' that's blocked on one side be starving carbs 1 and 2, or is that really unlikely?

I want to have something else to check if the fuel levels in carbs 1 and 2 turn out to be correct.

 

[posplayr]

Z1 sells a float level gauge for less than $10.

http://www.z1enterprises.com/detail.aspx?ID=4160

HTH

I would be embarrassed to say I ordered that and really ****ed if it did not fit.

But the take away is that it doesn't matter the shape of the tube or fitting as long as the end of the tubing is above the float height. That is the simplicity of the device.

 

[Kaiser Sosei]

Z1 sells a float level gauge for less than $10.

http://www.z1enterprises.com/detail.aspx?ID=4160

HTH

Those state they are for VM carbs which the OP should not have on his '81. Is the drain hole the same size on the CV carbs?

 

[RipRoaringFun]

Anyone ever find that the 'T' connector that supplies fuel to carbs #1 and #2 gets partly blocked? The gas line runs from the tank down to a 'T' between carbs #2 and #3.

If the left side of the 'T' is blocked partially it will mean the float bowls for carbs #1 and #2 will not fill up correctly.

I'd doing my fuel level check today but I'm wondering
Could a partly blocked 'T' make cylinders #1 and #2 lean?

 

[Tom R]

Anyone ever find that the 'T' connector that supplies fuel to carbs #1 and #2 gets partly blocked? The gas line runs from the tank down to a 'T' between carbs #2 and #3.

If the left side of the 'T' is blocked partially it will mean the float bowls for carbs #1 and #2 will not fill up correctly.

I'd doing my fuel level check today but I'm wondering
Could a partly blocked 'T' make cylinders #1 and #2 lean?

I thought I had the same problem once; but as it turned out the plug caps on the 3,4 side were loose - both of them. The caps just screw into a copper core wire - only takes a few minutes to check.

I had the carbs off for cleaning several times, replaced all fuel hoses and filters though they were fairly new, and even went to the trouble of cutting the fuel hose too short so it would kink when it got just warm enough to not get me to work.

I guess it could be blocked; but it's a relatively large opening. Do you have an in line filter?