No gas!

[Andreas Piepke]

Hi Paul,

Thanks for the input! Fuel isn't leaking from the overflow. I have a tube on it. When the bowl fills up, fuel is starting to accumulate under the carb. I can't exactly identify where it is coming from. It might be leaking due to a bad fit of the fuel line. I will try Teflon tape to see whether this helps. It could be overflowing somewhere, thus, my question about the float needle.
I did set the floats according to the manual, asking to put the carb on a level surface and make sure the floats are level when touching the needle. I haven't tried the "blow in method" yet as I didn't know about this. Sounds reasonable but now the carb is back on. The tickler came apart (the pin fell out) so I will have to take the bowl off again to fix this.

I appreciate your advise

Andreas

[harrO]

Where is the copper siphon tube that should be in the carb  body? Good Luck! Harry

[Andreas Piepke]

There is a small tube attached to the bowl. Is that what you mean? According to pics on Al Buehner's web page this is where it should be for a 36 mm Big carburetor.

Thanks for helping brain storm on this!

Andreas

[harrO]

On my set up the tube is fixed to the carb body. I believe it serves to siphon gas from the carb bowl. At the end of the tube (in the bowl housing) is a small hole. Make sure this is not plugged. Harry

[Andreas Piepke]

Hi All,

After some testing I excluded some possible problems brought up by some in earlier posts and identified one issue.
1) There were no rags in either the intake or exhaust port.
2) I made the exhaust accessible and used a plumbing implement to probe its inside. See the photo:



I could insert the thing until it hit the area were the end pipe attaches. Perhaps there is some baffle or something there. Probing and rotating the device brought not organic matter (nuts some nest or stuff like that)to light.
I then fashioned a "gas attachment" allowing me to blow into the exhaust:



I could blow through the pipe. Opening the spark arrestor at the end did not lead to a perceptible increase of flow impedance.
From these observations I would conclude that the exhaust is not blocked.

3) I took the carburetor off again and tried Paul's "blow in" test to re-check the float level. Whenever the floats becomes horizontal (with the carb mounted on a level surface) I can feel the float needle closing. The floats need to press a little further down until the needle closes fully. I conclude that the float level is OK. I then put the float bowl back on and filled the carb with gasoline, using a syringe:



I could fit 40 ml of gas into the carb until the needle closes. Is this a reasonable fuel volume in the bowl to allow reliable operation?

Continuing to fill the tube in 5 ml gasoline increments showed that they would slowly seep into the bowl at a rate of about 0.8 ml/min. This continued until I had filled in another 22 ml of gasoline into the bowl. At that point the bowl overflowed through the little brass tube attached to the bowl. This shows that the float needle doesn't properly seal. Now comes the issue: Al Buehner's web site lists a 7 mm triangularly shaped float needle while mine has 6 mm and has a four point shape. Would anybody know where I could get a rubber or Viton tipped replacement from?

And one more important point: am I missing a tube attached to the carb as Harry pointed out? The parts list isn't clear so I have no way of determining how the carb should look like. Could someone perhaps post a photo of a complete and working carb's underside? Mine is a Bing 54, type 2, 36 mm, ID 102.

Thanks for your input!

Andreas

[skiracer]

Get a real carb, and have that one dipped in bronze and send it to a museum......

1976 MC 5 Original Owner
1982 Suzuki PE 175
1976 Penton 175 GS
1976 Penton 250 GS

[harrO]

Hi Andreas...If you could post a picture of the bowl that would help me to explain or at least know if I'm on the right track. I'd post pictures if only I knew how! Harry

[Andreas Piepke]

Here a picture of the underside of my Bing 54:



Is some component missing e.g. some pipe?

Here a picture of the filled float bowl. The little brass tube is the overflow. Once the liquid reaches this level it drains through the tube out of the bottom.



To post an image you need to host them on a web site like e.g. Photobucket (a free service):
1) In your POG posting click on the "Insert Image" icon. This will insert #91; img #93; #91; /img #93; into your post.
2) Post your image to Photobucket.
3) While in Photobucket, click on the image you want to post.
4) To the right of the picture you selected will be a list of options. Left-click on "Direct". This will put the appropriate URL into your buffer.
5) Go back to your POG post and insert the URL by right-clicking and then pasting the URL of your image between the #91; img #93; #91; /img #93; command. The picture will now show up directly in your post. You need to either preview or post the text to see the result.

Cheers

Andreas

P.S.: I am sorry for the #91 and #93 statements. This HTML code for "[" and "]", respectively. It renders correctly in "Preview" mode. However, the web site modifies the text when posting and the HTML symbols aren't rendered correctly any more. This is probably an issue with some optimization this web page tries to perform. The procedure is correct.

[harrO]

I hope I didn't get your hopes up. My 24mm includes a brass tube that is fixed in the body that fits into that cast hole in the bowl when assembled.  There is a small hole (also shown in your picture) at the bottom of the casting that must be clear... at least on the 24mm. Check that this is clear with a fine wire or drill bit. Harry

[Keith Meatyard]

Hey Andreas, I know this has already been mentioned, but you may not be letting enough fuel overflow and run down into the intake passages to fire the motor.  I have a 74 175 KTM Jackpiner, and it does not have a choke, as I noticed yours doesn't either.  Anyway, to start that motor, I have to let the carb overflow by holding the tickler until a puddle forms on top of the cases, under the carb.  While the fuel is dripping out the overflow tube (in the bottom of the bowl), fuel is also running down inside the intake passages.  Even then it takes a couple of kicks, and when it does fire, I have to keep it running by using the throttle.  Once warmed up, it screams and idles like a kitten.  I will then take a rag and soak the excess off the cases.  The 175's that have chokes do not require the puddle of gas under the carb, maybe just a tad if bike was completely run out of fuel, meaning no residual in the crankcase.

Second, be sure you have spark from the motoplat, if you still have one.

Keith Meatyard

[Andreas Piepke]

Thanks Keith! I will first have to fix the float needle. As it's not sealing properly any more whenever I use the tickler the carb just keeps overflowing. I'll try your technique once the carb is back on.

Cheers

Andreas

[Paul Danik]

I used to have a MC5 250 and the starting ritual was as Keith described, plus, I would have the front wheel lower than the rear if possible. Also, once it fired, I would just hit the tickler to keep it running when it tried to die out. Awesome running machine, and easy to start once the "ritual" was preformed.

  On the first morning of the 1973 ISDT, when it was time to start my Sachs powered 125cc Penton I kicked and kicked, with no results. Erwin Leichner (sp) from KTM who was on the start line with us, ran over and indicted to me to flood the engine with the tickler, which I did, and it fired on the next kick. First morning jitters.....

Paul

[Andreas Piepke]

Hi All,

I should, at this point, change the subject line of this post to "too much gas". I have a little Bing mystery for this group. My 36 mm Bing 54 carburetor (2/36/102) has a leaky float needle, as described in previous posts. So I purchased a new one from Bing USA. The next image shows a comparison of what I got (left) to what was in the carburetor (right):



These components seem to have no similarity. The original Bing part needs to be pressed into the carb body while the holder, I found installed, is screwed in (by means of a 10 mm thread). The following image shows the carb body with the threaded bore accepting the float needle holder:



The last image shows the float needle installed in the carb. The little clip on there prevents the needle from falling out. However, the is no connection to the floats other than them pressing via the tap on the spring loaded stem. The float needle I found in there has a quadratic rather than triangular cross section.



Has anybody in this group ever seen such a setup? The Bing people cannot identify this. Or could this just be some odd modification done by a previous owner, using a non-Bing part? Can anybody identify the needle holder I have?

Thanks for your input

Andreas

[brian kirby]

That is a Mikuni float needle/valve. You can stay with a Bing, but you need to get rid of that one and get a new one, or better yet, get a Mikuni.

Brian

[Andreas Piepke]

Hi Brian,

Thanks for ID-ing the needle. Replacing the existing part with the appropriate Bing component won't be easy though. The existing threaded bore in the carb body is larger than the Bing needle holder. I will have to fashion some kind of sleeve accepting the holder that engages the thread. I will need to understand whether there is enough room for that.

Thanks for the input!

Andreas