Beitrag von: Kurt in S.A. am 28 Juni 2020, 19:27:08
Thanks...Kurt
Beitrag von: Hans Otté am 28 Juni 2020, 20:42:01
Zitat von: Kurt in S.A. am 28 Juni 2020, 19:27:08
Carb is 1/22/44. I'm thinking I might not have the idle air mixture set right. My Bing manual says the setting is 1-1/2 turns out. Does that seem right? Usually that's a starting point, though. How does one go about fine tuning that? Do I get the engine warmed up and change the number of turns in (cuts out some air to make richer) and out (lets more air in to make leaner) and find the spot where the RPM goes the highest? Maybe then a slightly bit richer from that point?
Thanks...Kurt
Hi Kurt,
the values you are mentionning seems to be right, my docs are saying same.
But do any basic adjustments to the carb's settings only when the engine is in good working condition and really warmed up.
Oel temp should be stabilised around 70 to 80° to get an stable idle. A short ride will get the engine to that point.
HansO
Beitrag von: Kurt in S.A. am 28 Juni 2020, 21:02:25
Kurt
Beitrag von: 4Taktix am 28 Juni 2020, 23:58:35
Zitat von: Kurt in S.A. am 28 Juni 2020, 19:27:08Exactly like that !
....and find the spot where the RPM goes the highest? Maybe then a slightly bit richer from that point?
Cheers,
Sascha
Beitrag von: Kurt in S.A. am 29 Juni 2020, 19:22:33
Kurt
Beitrag von: Hans Otté am 29 Juni 2020, 20:00:16
Zitat von: Kurt in S.A. am 29 Juni 2020, 19:22:33
Just checked...the adjustment was at about 3/4 to 1 turn out. So, I reset it to 1-1/2 turns out. Will need to final adjust at the next ride.
Kurt
Hi Kurt,
when there a solution has been found, eventually a problem may be solved !
But don't forget : one resolved often means two new ones will propperly appear, soon.
Be happy, don't worry and good luck,
Hans
Beitrag von: Kurt in S.A. am 29 Juni 2020, 21:03:40
The other thing that I'm trying to resolve is that the engine surges a bit when running in lower gears at slow speeds in the neighborhood. I was wondering if maybe my idle jet was too small...I don't know precisely if it is the 35 called out in the specs...it's been a while. Then I thought about the mixture setting and how it might be affecting part throttle running. I understand that the regimes of carb operation - idle jet, needle jet, main jet - all overlap at various throttle positions. So, I'm trying to get the carb set where it should be and go from there.
Kurt
Beitrag von: strichzwojan am 02 Juli 2020, 19:31:37
find the setting as described. then make a test: try to find a "mountain road" an let the bike roll on high revs downwards. If the setting is too weak, there will be "bangs" to be heard in the muffler. Too, if the washer between exhaust and cylinderhead is worn out.
You will see, that there is a very small turn between "too weak" and perfect.
Good luck,
Jan
Beitrag von: 4Taktix am 02 Juli 2020, 19:49:27
One other potential cause are the ignition-advancer-springs.
If they lost tension over time, the fly-weights need lowers revs, until they swing back to their "late" position - the ignition is advanced although it isn't supposed to.
To check this, remove the generator lid, connect a strobe gun and aim on the advancer. Works best in a shaded or dark area.
Now rev it and watch the weights while closing throttle and rpm drops.
If they don't swing back till shortly before idle-rpm, it maybe worth a try to renew the springs.
But I suppose there will be an improvement already by setting idle more rich.
Next step could be to lift the needle one position - enrichens the next regime above idle. If required.
Cheers,
Sascha
Beitrag von: Kurt in S.A. am 02 Juli 2020, 20:09:23
In the position I found it, the idle mixture was screwed in too far, shutting off air making the idle circuit more rich.
The surging around the neighborhood at slow speed seemed to begin middle of last year when I lowered the needle from the 3rd to the 2nd position. Ever since I got the bike, the mileage was around 50 mpg (US). I felt it should have been better than that. So I made the "crude" adjustment with the needle. Now the gas mileage is more like 63 mpg. I spend most of my time on 2/3-3/4 throttle so I'm likely on the main jet as well. I was thinking that the needle adjustment might have affected the low range idle circuit.
I'll have to consider the advance springs...they might be original for all I know!!
Kurt
Beitrag von: Kurt in S.A. am 19 Juli 2020, 15:35:49
--- update --- As I think about it, if it didn't make any difference when I moved it with engine running, resetting it to 2 turns out probably won't make any noticeable difference. :spinnt:
Kurt
Beitrag von: 4Taktix am 20 Juli 2020, 14:23:26
sounds like something other then the mixture screw is limiting/adjusting your idle-rpm.
Not sure what is stock on R25/2 - but check, if the mixture (idle-air) screw has a longitudinal bore with 2 tailings beneath a little tin cap.
Maybe this is clogged and prevents proper setting.
See this thread, post #19, pic #7
https://bmw-einzylinder.de/forum/index.php?topic=16214.0
Cheers,
Sascha
Beitrag von: Kurt in S.A. am 20 Juli 2020, 17:05:42
I'm typing a second time...tried uploading a picture that was already on the forum. :(
Anyway, I don't have that little "cap". I'm familiar with this on my R69S. In the link below, look at the first picture. I don't see how there's any room to fit a cap on it. I thought the cap was more or less a crude filter to keep debris from getting into the hole that is on the screw.
https://bmw-einzylinder.de/forum/index.php?topic=18077.0
This is the way the bike came to me. I might just back the screw fully out and examine it more closely.
Kurt
Beitrag von: 4Taktix am 20 Juli 2020, 18:18:03
seems there are two different screws available, a short and a long one. Whereas the short is assigned to R24.
Check this out:
https://www.ulismotorradladen.de/artikelliste/Vergaser_Luftfilter_BING_Ersatzteile.aspx?BildNummer=V030
both versions displayed on that site. --> "Gemischregulierschraube"
Looks like you got the short one, thus no room for the cap.
No Idea, if the carb works as intended with each of them.
The explo shows the long version including the cap - parts 30,31,32. Which is correct for R25/2.
Position the mousepointer onto each particular part in the explo until it's highlighted, then click.
Will display the german term, order-number and price in the right window.
Regards,
Sascha
Beitrag von: Kurt in S.A. am 20 Juli 2020, 18:52:42
I'll have to take out my short screw and see what's going on. I suppose I could "borrow" the set up from my R69S and see what the difference might be.
--- When I look up the parts on the Benchmark Works site here in the US, they list the following:
13 11 0 039 180----carburetor idle mix screw Bing R24-R25/2 R27
That seems to suggest that there's only one screw used for all the singles. Something's not right here.
Kurt
Beitrag von: 4Taktix am 20 Juli 2020, 19:21:14
= Carb and Sparparts, Aircleaner...
So its like a general example for Orientation.
Concerning the part-numbers you were absolutely right.
Recently I learned my lesson here: Rabenbauer.com uses original BMW Part-numbers.
So you can spend the nightime to cross-check against other dealers via Searchterm, Drawings and sketches, until you are halfway sure, to order the desired part ;-)
I never heard the carb-model-terms you mentioned. Maybe it's something BING-internal.
But it's common, that many parts are equal among different carbs. As e.g. the main jets.
Also in my link it says for the long screw: "Gemischregulierschraube für BMW R25-R69S, lang", so there's nothing odd with it.
Borrowing the parts from your Boxer is what I'd do first.
Sascha
Beitrag von: Kurt in S.A. am 24 Juli 2020, 00:30:38
https://www.bmwbike.com/index.php?e=mhs#nav-sub2
Mark shows that beginning with the R25/3, the longer screw was used.
I haven't tried removing the current mixture screw on my bike but will get to it. When I do, I'll also pull the air cleaner and then spray some brake cleaner in from the mixture screw side and see if there's anything coming into the carb throat.
Again, there's conflicting info depending on where one goes to look.
Kurt
Beitrag von: Kurt in S.A. am 31 Juli 2020, 17:07:47
I'm anxious to give it a ride to see what kind of difference it might make.
Kurt
Beitrag von: 4Taktix am 31 Juli 2020, 17:49:53
Now tell me you are shy ! ;D
C'mon, Remember the Alamo ! :attacke:
Sascha
Beitrag von: Kurt in S.A. am 31 Juli 2020, 19:04:56
Kurt
Beitrag von: Kurt in S.A. am 23 August 2020, 16:10:03
I'm not real sure what's going on...might have to take the carb apart.
Kurt
Beitrag von: rolf am 23 August 2020, 18:23:30
your idle screw without cap is original, forget what other people say....2. this one or with cap wasn´t the problem. ...they were (as you do) interchangeable without any problems.
I did not really understand your problem....the idle did not change when turning the screw?
What is when you turn it nearly to the ground? Also no change?
Rolf
Beitrag von: Kurt in S.A. am 23 August 2020, 21:42:01
Interesting about the air screw. I called Bing here in the US and they said for my carb number, I needed the longer one with a hole. There is conflicting information on the web at the various parts sites.
Yes, with engine idling, turning the air screw either way, numerous turns results in no change to the engine RPMs. I even lightly seated the screw and no change to the engine running. In the case with the original shorter screw, I'm not sure what it's function is. Without any hole down the middle, it is very difficult for air to pass between the threads of the screw from the outside to the inside of the carb. Therefore, the sharp point of the air screw must be opening/closing some passage within the carb. And since turning the screw...either of them...results in no engine changes, that passage must be plugged.
Kurt
Beitrag von: rolf am 24 August 2020, 00:06:46
the little hole inside the idle screw is NOT for air INTO the carburetor....it is for gasoline OUT of the Carburetor
The only air for the carb comes the holes in the Carb.....the hole that you can close with the idle screw by turning clockwise
if your engine (OR CARB) did not react by turning the idle screw to the ground.....you get air on another way to the carb....in german "Nebenluft":::MOSTLY OVER THE FLANGES OF THE CARB.
proof it:start the engine....at idle spray a little bit start pilot, brake cleaner or something else inflammable ob the flange or all of the carb.....when the idle is changing....you got where the carb gets his Nebenluft....then ask again to eliminate this
Beitrag von: Kurt in S.A. am 24 August 2020, 00:24:13
OK, good idea. I hadn't thought about air getting into the carb via other paths. I'm aware of this on my twin cylinder bikes...will have to check that out. It might take a bit of time before I can get back to try this.
Kurt
Beitrag von: rolf am 24 August 2020, 10:11:34
Beitrag von: Kurt in S.A. am 07 September 2020, 16:38:21
Kurt
Beitrag von: 4Taktix am 07 September 2020, 17:06:52
I suppose that some part of the idle-system is still clogged, that makes the setting of the idle-mixture-screw effectless.
Sascha
Beitrag von: rolf am 07 September 2020, 17:41:56
Beitrag von: Kurt in S.A. am 07 September 2020, 18:31:29
Kurt
Beitrag von: rolf am 07 September 2020, 19:41:43
SPRAY A LITTLE BIT ON THE GROUND AND THEN TRY TO :kopfhau: made it burn with a match...only for sure
Beitrag von: Kurt in S.A. am 07 September 2020, 20:25:23
Kurt
Beitrag von: rolf am 08 September 2020, 10:21:50
I´ll think about it.
Beitrag von: rolf am 14 September 2020, 23:09:30
paint konic part of the idle mixture screw with an Edding.....screw then the screw into his hole until you ment it is full screwed in.....then screw it out.....is there any ring visible on the Edding marking?
Beitrag von: Kurt in S.A. am 15 September 2020, 00:43:19
Not sure what you mean by "edding". Are you referring to some kind of blue-ing compound? I guess you're wondering if the screw actually seats.
Regardless if the screw seats, it seems that turning it 1-2 turns from the starting point (about 1-1/2 turns out) resulted in no RPM change.
Kurt
Beitrag von: strichzwojan am 15 September 2020, 09:22:06
BTW, edding could be used too, to mark breakpads to ensure correct position and wear in the break drum...
Jan
Beitrag von: rolf am 15 September 2020, 09:30:28
Beitrag von: Kurt in S.A. am 15 September 2020, 13:36:02
Kurt
Beitrag von: rolf am 15 September 2020, 13:54:26
paint konic part of the idle mixture screw with an Sharpie.....screw then the screw into his hole until you ment it is full screwed in.....then screw it out.....is there any ring visible on the Sharpie marking? :P
Beitrag von: Krottenkopp am 15 September 2020, 13:58:26
Gruß Heiko/2
Beitrag von: Kurt in S.A. am 15 September 2020, 14:00:59
Kurt
Beitrag von: Kurt in S.A. am 26 September 2020, 16:17:15
Kurt
Beitrag von: rolf am 28 September 2020, 01:38:07
once again....no idle changement when you screw in the idle screw? And also no "Nebenluft"? It cannot be so!
Beitrag von: Kurt in S.A. am 28 September 2020, 12:40:05
As for a thick vs thin ring, could be that the interior hole in the carb has worn a bit over the years. I did not retry the screw to see if it made a difference in the idle speed...I had done that before with this very same screw and it made not change. One thing I would say is that after my ride, the surging I have been getting when returning to my neighborhood was absent. So, I'm not sure what to make of that.
One other "funny" thing happened on that ride. I keep track of my gas mileage and use the results of a fill up to calculate when the tank will go to reserve the next time. I write that number on a piece of tape on the gas cap. When I left home this time, I noticed I was relatively close to the number on the tape so I headed straight for the gas station. Less than a kilometer from the gas station, the bike stumbled and stopped running. I have a clear plastic filter and could see there was no gas in it. I was shocked because the odometer read earlier than my piece of tape!! Hmmm... I was on a hill down to the gas station so I just put in neutral and coasted to the pump.
When I got home, I rechecked my calculations. Turns out the number I wrote on the tape was "exactly" the distance to reserve. Typically I write a number that is say 20 kilometers before reserve so I have a bit of cushion. So, I goofed this time in picking my target mileage for heading to the station. I could have turned the petcock to reserve to get another couple of liters of fuel...but I generally don't drive deep enough into a tank to need reserve so I didn't think of it. Plus I had the downhill coast to the pump so I didn't have to push the bike for that distance!!
To complicate things, I have been doing some tweaking of the idle screw and checking for leaks which meant that I burned up fuel sitting in the driveway. That's why I burned the fuel in the main tank earlier than I had predicted. Live and learn!
Kurt
Beitrag von: rolf am 28 September 2020, 13:08:42
Kurt....I ask for a translation to the forum....my english is not good enough
Beitrag von: 4Taktix am 28 September 2020, 15:54:17
Nix, was zur Problemlösung beitragen würde - zumindest kann ich das nicht erkennen.
Beitrag von: Kurt in S.A. am 28 September 2020, 17:29:08
Kurt
Beitrag von: rolf am 28 September 2020, 17:32:05
As for a thick vs thin ring, could be that the interior hole in the carb has worn a bit over the years. I did not retry the screw to see if it made a difference in the idle speed...I had done that before with this very same screw and it made not change. One thing I would say is that after my ride, the surging I have been getting when returning to my neighborhood was absent. So, I'm not sure what to make of that.
Beitrag von: Kurt in S.A. am 28 September 2020, 21:33:23
Kurt
Beitrag von: 4Taktix am 29 September 2020, 12:47:11
very simple: detach the carb - slide in idle position - one finger into the intake-side, one other into the outlet-side, then try to move the slide back and forth.
Repeat in various positions. I suppose you will notice that the sideplay decreases, the higher the slide-position.
If so, there is definitelty some wear. Replacing the slide is easy, but the wear will also be in the carb-body, which is harder to eliminate.
Maybe for 35 bucks it's worth a try - depending on the quality. Does the internet have rumours about that replacement carb or that dealer ?
Another possible root cause may be a crack in the carb-body. But you'd have noticed that by rpm-change while spraying with the cleaner or whatever flammable you tried.
Also check the cable-inlet on the top-lid - there's a rubber sleeve available to prevent air from bypassing the slide that way.
You could pre-check this by wrapping tape tight around the cable-inlet.
Regards,
Sascha
Beitrag von: Kurt in S.A. am 29 September 2020, 22:38:45
I verified that the hole from the air bleed is open to the throat of the carb. But there's another hole upstream of that. This is a bad picture...best I could do. The air flows from the bottom of the picture to the top. What you're seeing is the top of the atomized in the bottom of the chamber. I've circled what appears to be a hole downstream of it. Note that the hole from the air mixture screw is a little further downstream of the hole that I've circled. I sprayed cleaner in the circled hole but didn't see where any of it came out somewhere else.
Lastly, I thought I should check the flatness of the carb flange. It looked flat! But I rubbed it on pieces of 600 grit sandpaper with some acetone, going each direction a number of times. It did appear that it wasn't flat. I continued until I got shiny material all the way around the main throat opening. Lastly, I put some blue hylomar sealant on both sides of the carb spacer as well as around where the carb cap screws onto the cap. I'm thinking that maybe air was leaking around this flange.
Kurt
Beitrag von: rolf am 29 September 2020, 23:37:00
THE "Mischkammereinsatz" is in right position?
ps
danke, Sascha :-\\
Beitrag von: Kurt in S.A. am 30 September 2020, 00:03:48
Kurt