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Donovan
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Hello,

I have a R25/3 in need of a float needle. I understand the R25/3 came with two different carbs. A Bing 1/24/41 or a SAWE K 24 F. I have the SAWE K 24 F carb and I am in need of a float needle. The available replacement needles I have seen look similar to the one I have but are larger in diameter and longer. I have not been able to locate a float needle for the SAWE carb. Does anyone on this forum know a vendor or supplier that has parts for the SAWE carbs?

Thanks,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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Donovan -I don't know many

Donovan -

I don't know many suppliers from Germany, but you might try Vech. I checked S.Meyer's website and they list a float needle part 0V39188 as being for the R25/3 and other bikes. It doesn't distinguish it as Bing or SAWE. The OEM part number for the float needle is 13 11 0 039 188 so that's where their part number comes from.

http://www.meyer-bikes.de/index.php?page=static&path=home

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Donovan
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Kurt, A week ago I ordered

Kurt,

A week ago I ordered the part from Vech. He only had one part # listed for R24-R27 and when it came it looked just like the picture of the one S Meyer sells. This is the needle for the Bing carb. I will call Vech tomorrow and see if he has any leads.

Thanks,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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I did some searching...came

I did some searching...came up with the following:

http://bmw-einzylinder.de/forum/index.php?topic=3218.0

In reading this thread, Mark Huggett's site was mentioned:

http://www.bmwbike.com/index.php?l=en

Google showed some mention of the SAWE carb on this site, but I don't see it right away; it's a forum, maybe there's a way to search:

http://www.125er-forum.de/threads/2478473-quick-lock-koffertraeger-honda...

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Donovan
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Kurt, Thanks for the reply. I

Kurt,

Thanks for the reply. I used Google translate to read the German thread. I appreciate the link to that, though it seems parts for this carb may be unobtainable.

I did find a part number on Mark Huggett's site for this float needle, # 13 11 0 039 389. So it does have a different BMW part number. Also that thread seems to confirm what I was thinking, which is parts are not interchangeable between the SAWE and Bing carbs.

It is difficult to believe something so small as a float needle could take this bike off the road. Hopefully I will be able to find something before this happens.

My current problem is the needle doesn't fully seat and the carb will leak after a few minutes if the fuel is left on and the bike will flood if it isn't started quickly enough. The previous owner tried to fix this by using a Bing 7g float in place of the original brass float and it does help, but the issue still exists.

The Bing needle *might* be able to be machined to fit, but I do not have access to a lathe. The bottom cone shape of the float needle will completely cut off the fuel flow and the notch will work with the float, it is just the needle shaft is too long and about twice the diameter it needs to be to problem engage the fuel bowl top.

I still have hope that somewhere I will be able to find a float needle for this carb.

Thanks,
Donovan

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1955 R25/3
1971 R60/5

speight1823
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R25/3 carb

I own an R25 and an R 27 but have never seen a SAWE carb so my advice may be useless.
On the Bing single cylinder carbs where the petrol enters on the bottom of the petrol bowl a very common problem is that the cut off needle wears on the tapered plug at the bottom of the needle .
This results on the needle rising too much and hitting the top of the petrol bowl cap not allowing the needle to seat.
Very easy solution is to cut about 1mm off the top of the needle.
If it still not cutting off , but the needle is seating cut a small slot under the needle and lap it in with some Brasso.
Hope this helps
Bill
South Africa

Donovan
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SAWE Carb Float Needle

speight1823 wrote:

I own an R25 and an R 27 but have never seen a SAWE carb so my advice may be useless.
On the Bing single cylinder carbs where the petrol enters on the bottom of the petrol bowl a very common problem is that the cut off needle wears on the tapered plug at the bottom of the needle .
This results on the needle rising too much and hitting the top of the petrol bowl cap not allowing the needle to seat.
Very easy solution is to cut about 1mm off the top of the needle.
If it still not cutting off , but the needle is seating cut a small slot under the needle and lap it in with some Brasso.
Hope this helps
Bill
South Africa

speight1823 wrote:

On the Bing single cylinder carbs where the petrol enters on the bottom of the petrol bowl a very common problem is that the cut off needle wears on the tapered plug at the bottom of the needle .

The SAWE is the same.

speight1823 wrote:

This results on the needle rising too much and hitting the top of the petrol bowl cap not allowing the needle to seat.

My needle has a distinct groove worn into the tapered plug. I suspect from many years of wear in the same location.

speight1823 wrote:

Very easy solution is to cut about 1mm off the top of the needle.

On the SAWE the top of the needle actually seats into the top of the float bowl by about 1-2mm. I can only assume this is used as a needle guide. Does the Bing do something similar?

When I install the Bing float needle I bought from Vech in the SAWE carb without the float bowl top mounted, it does cut off the fuel quite well. However, the diameter of the needle is too big to fit into the guide in the float bowl top and it will stick, preventing the needle from moving at all. Your suggestion of cutting the needle is interesting and I did not consider it, however, if the needle guide is necessary this might actually work. Since I have purchased the needle already, it seems like a worthy experiment. I also need to take some pictures of this carb and post them.

speight1823 wrote:

If it still not cutting off , but the needle is seating cut a small slot under the needle and lap it in with some Brasso.

I am not sure I understand what you are saying here, where would you cut the slot?

Thanks,
Donovan

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1955 R25/3
1971 R60/5

speight1823
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R25/3 carb

The Bing and SAWE carbs seem to be similar in design.
I would suggest you take your SAWE needle and float top to your local machine shop and ask them to lightly clean up the cone on the bottom of the needle to remove the ring you were talking about. Should not take longer than a few minuets.
Lapping in the needle is similar to lapping in automotive valves but you want to use a non aggressive lapping medium like the polish used to make brass shine. You don't want to put back the ring on the cone.
You need the small slot on the bottom of the needle 1) So you can check that the cone is sitting snug on the valve seat by moving the needle with a screwdriver , from under the cone , with the petrol bowl top in place. If you get sideways movement chances are you will have to remove a small amount off the top of the needle .
2) You will need the slot to rotate the needle during the lapping process , clockwise and anticlockwise. During this process the bowl top will need to be in place.

I think the little BMW 250 bikes are great little bikes with a charm all of their own. For around town or short trips I prefer them to my R69S
All the best
Bill

Donovan
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Bill, I understand now, thank

Bill,

I understand now, thank you.

I spoke to Vech yesterday and also heard back from Mark H and S Meyer. No joy on the parts for a SAWE but I believe I can make the Bing needle work with some modification and/or repair the SAWE needle. Hopefully I can buy enough time to find a proper Bing carb before something else fails on the SAWE.

I agree these little 250s are great. I have a R60/5 for "normal" riding. This bike is for around town and country rides with a buddy who owns an R27.

There is something about the BMW single I have not encountered in any other bike, and currently, they are my absolute favorite to ride, as long as I do not need to be there in a hurry;)

Thanks,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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Donovan - I'm not sure I

Donovan -

I'm not sure I agree on riding the singles! It's certainly fun, but requires a great deal of work and concentration. The shifting is quite different to make smooth shifts. Forget trying to go from 1st to 2nd...not sure how it is on your bike but my R25/2 has virtually no overlap in RPMs/speed between these two gears. It has to do with the internal ratios that makes it so difficult. Plus, I've had a few instances where I've been stranded...three I've been able to fix and get back home while the fourth I was fortunate to have friend just happen by and he got his trailer. I'm not really sure what to expect when I get on the bike!

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Donovan
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Kurt, I agree about 1st/2nd

Kurt,

I agree about 1st/2nd gears. And of course 1st is incredibly short. Just good for starting off from a dead stop. Most of my rides on the R25 are in 2nd and 3rd gears. On some country roads I'll use 4th until I get to a hill with any sort of length or grade and then it is back to 3rd. However, my bike does shift very smoothly. My friend with the R27 has commented on this a couple times. I run a 85/90W GL4 gearoil I got at Napa. They actually still carry the stuff in quart bottles.

The marks on my speedo are accurate indicators for shifting speeds and I find the R25 is perfectly happy doing 45 mph in 3rd gear.

Fixable break downs are nice, and of course having a friend with a truck or trailer helps. I do like that these bikes are fairly simply straight forward machines.

Having grown up around British cars I have a certain expectation when it comes to reliability.

BTW -- I have enjoyed reading your numerous threads about the R25/2. That green is a terrific color.

Cheers,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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Thanks...yes, I like the

Thanks...yes, I like the green color. One of these years, I hope to make it back to Montabaur where the bike was part of the police force there. I'm interested in knowing more of its history, especially the maintenance. I know that someone was inside the engine in the past...the cylinder is first over already. I wrote about acquiring the bike in the Club's magazine. That was Part 1...I hope I have a chance to add a Part 2!

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'78 R100/7 '69 R69S '52 R25/2

Donovan
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Bing Located

I managed to source a Bing 1/24/42 but it was incomplete. It was missing the jets and some other parts, which I ordered from Bing.

I now have all the parts for this carb but I'm unsure of a couple of baseline settings.

I did some looking on this forum and found the setting for the needle is position #2, but is that 2 from the top or bottom? My needle has 4 positions.

I see the idle mixture screw is 1.5 turns out but what is the starting point for the idle speed setting?

I think that should be enough to get me started, hopefully I can report back that I have a functioning Bing.

Thanks,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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VBMWMO #7032
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Settings can be found on this

Settings can be found on this scanned page.

http://www.flickr.com/photos/67726688@N00/66174400/in/photolist-6RakW

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Donovan
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Thanks for the link to that

Thanks for the link to that sheet, I had not seen it before.

I'm also glad I checked it because Bing sent me the wrong needle jet. They sent a 2108 rather than a 1208. So I will have to wait until the proper needle jet arrives to test this carb.

Thanks again,
Donovan

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1955 R25/3
1971 R60/5

schrader7032
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I always wondered if 1208 and

I always wondered if 1208 and 2108 was a misprint. Did Bing actually say there are two different needles?

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

Donovan
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Yes, Bing did say there are

Yes, Bing did say there are different needles and needle jets. The one in the body I bought looked identical to the 2108 but was numbered 1308. The sheet you linked to shows different needles jets and needles and so I went over the parts on the phone with the guy at Bing. He said the carb number 1/24/42 designates what parts are supposed to be in it so ideally you just have to give Bing those numbers and the type carb you get the right stuff. He also had me confirm the needle itself was correct by counting the number of notches under the clip holes.

I think in this case the guy pulling the parts just misread the part number since they are so close. Bing says there are differences in the hole diameters so I'm gonna wait until I get the right parts to try running this on the bike.

Someone had really changed the original setup of this carb since a 1/24/42 should only be on an R25/3 but it had a 115 main jet, a 1308 needle jet, and a 120 idle jet.

Thanks,
Donovan

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1955 R25/3
1971 R60/5

Donovan
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OK, so I had some cabin fever

OK, so I had some cabin fever yesterday and I decided to mount my rebuilt Bing on the R25/3 because it looked like I could easily change the jet needle when it arrives. So the current setup is:

145 main jet
1308 needle jet (will be replaced with a 1208 from Bing)
35 idle jet
Needle clip position 2 (count from the top)
11g brass float

Started on the first kick in 36F temps, not sure if that will be a problem when it warms up but I wasn't expecting it to start quite so easily. Idled a little high once totally warmed up and there seems to be a dead spot in the middle range, but I don't expect it to perform quite right until I have the correct needle jet installed.

I've attached a couple pics of the Bing 1/24/42 beside the SAWE K 24 F. Despite the similar appearance there are no interchangeable parts between these 2 carbs. Even the float clips are different because of the different diameter of the float needles. It is interesting to note that the float in the SAWE was a 7g black plastic float from Vech. It seemed to be OK, but I thought it was interesting because I thought all the singles had 11g floats.

If the original brass 11g float I have in the Bing starts to leak I wonder if the 7g black plastic float will work or if the mixture will become too lean.

The SAWE is now my spare.

In the pics, Bing is on the left, SAWE on the right.

Cheers,
Donovan

  • carb-1.jpg
  • carb-2.jpg
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1955 R25/3
1971 R60/5

schrader7032
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VBMWMO #7032
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Vech sells plastic floats for

Vech sells plastic floats for the singles...they're the 7g version with a weight inside to make them the right weight.

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Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

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