The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: guyom on August 24, 2016, 01:35:50 PM
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Hi guys, I have a problem: i cleaned my carb (separately) so rebuilt then with new seals after cleaning... and now my choke does not work.
When the motor is cold, the choke does not help to start...
Another test, when the motor is warm, if i put the choke on, the motor chokes... and stop and i was thinking that the RPM should increase.
So i checked the discs (perhaps upside down) but i think no (if someone has a picture of good disc position, level in correct position, i'll take it) when i pull on the cable of each choke, at the beginning the RPM increases but quickly the motor chokes...
Or perhaps the mix air/gaz is not good (too rich ??) and when i restrict the air with the choke, there is no air at the end... and the motor chokes? Any other idea ?
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Correct orientation of the choke disc is easy if you understand how it works. Fuel enters via progressively larger holes at the bottom of the disc and the mixture exits via a tapered pear shaped slot at the top of the disc. The enrichers are correctly oriented when the pear slot is at the top of the disc and points towards the cylinder head. The animation below shows the enricher moving from the off position through the 4 progressively larger fuel holes and back to off again.
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Photos may be of help:
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Herés mine !
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Looks good but i want that wrong to answer my problems... Otherwise i need to look for something else.... Perhaps mixture screws : i found them at 3 turns so far from the 11/2 recommanded to start to find the good ratio ?!
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I forgot to mention that the levers are down of each, so inducate 5:00 for the Left one and 7:00 for the Right
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I forgot to mention that the levers are down of each, so inducate 5:00 for the Left one and 7:00 for the Right
That sounds correct for the off position as long as they both hit the stops at the same time.
3 turns out on the mixture screws sounds very rich even 1 1/2 turns out sounds too much but you haven't given us the model and year of the bike.
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Sure i've got a R65 1981
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There is a small dimple on the threaded end of the brass shaft that the disc is on .
The dimple is offset from the center of the shaft, the dimple should be towards the arm that the cable goes on.
The disc can be 180 degrees out, but still goes together .
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Lot's of Bing CV Enricher Circuit info on Snowbum's site.
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Sure i've got a R65 1981
I believe the base line setting for your mixture screws is only 1/2 turn out or 3/4 at the most.
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Thanks Barry. only a 1/2 turn ??? Whaaa ! It's not a lot and far from 1 1/2 or more. Do you suggest i start the setup at 1/2 and try to see if it's good ? Is it possible that with my setting (3 turns) the choke does not work with ?
Just to understand well : when the screw is closed (we can say 0 turn :-)), there's less air, so it's rich ? Or the inverse ?
Thanks for time
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Yes you should always start the mixture adjustment from the baseline setting. Gently turn in the screw until it stops and turn out by the specified amount. From that base line setting Turning further out richens the mixture and turning in weakens it.
If the engine doesn't idle reasonably well at the baseline setting there is usually something else wrong with the carb.
The enrichers are completely independent of the main carb and have no interaction with the idle mixture adjustment.
To be certain of your baseline setting for the mixture screw check your carb model no against this list.
1/2 turn
64/28/201, 64/28/202, 64/28/301, 64/28/302, 64/28/303, 64/28/304, 64/32/203, 64/32/204, 64/32/307, 64/32/308, 64/32/347, 64/32/348, 64/32/201 (US), 64/32/202 (US), 64/32/223, 64/32/224, 94/40/107, 94/40/108
3/4 turn
64/32/305 (UK), 64/32/306 (UK), 64/32/321, 64/32/322, 64/32/325, 64/32/326, 64/32/335, 64/32/336, 64/32/349, 64/32/350, 64/32/351, 64/32/352, 64/32/353, 64/32/354, 64/32/357, 64/32/358
1/2 - 1 turn
64/32/9, 64/32/10, 64/32/11, 64/32/12, 64/32/13, 64/32/14, 64/32/201 (UK), 64/32/202 (UK)
[edit]
1 turn
64/32/19, 64/32/20, 94/40/109, 94/40/110, 94/40/113, 94/40/114
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héhé thanks. just a question: where i can find the no of my carbs ?
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I will try to find the number and test the carbs. However, if i well understand what you write, the problem with my enrichers can not come from the setup of my carb so definitely i do not understand what's happen, the disc are in correct position, cables are ok... If you have any other ideas...
Anyway thanks for help.
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Have you checked that the idle screws are in order ? The tip is very fragile.
Have you ascertained that the tiny passageways for idle are free ?
Have you checked that the butterfly are set properly ?
If your carbs are clean and the brass is in order, the bike will start at once with the basic settings.
Of course she lay not run perfectly because the engine is not new and the gas today is not the same as it was 30 years ago, but it is a good baseline.
Last but not least, the P/N of the carbs are stamped on them, vertically near the top cover.
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The carb type number is on the web between the main venturi and the and the diaphragm housing.
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Hi Guys thanks Barry (again) i found the number... 64/32/325-and 326... so 3/4 turns for baseline and i will tune up with this. I also change the fuel hose. I will try the bike soon.
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Hi Georges thanks for help. Yes i checked the idle screws (clean and spring ok), the hole connected to the enricher discs, etc... that's strange... I found the number of the carbs : just 3/4 turns... but if the enrichers are not related to the cab tune up... that does change any things about the choke... i need to make new tests on road. Thanks for time.
By the way, another question : my silencer exhaust are shorter than stock ones (17" compare to 25" i think) i know that the total length of the exhaust can influence the tune up of the carbs.
--> Is that right ?
--> If yes, to your opinion, should i find the correct air/fuel ratio up or down the 3/4 turns ?
Thanks !
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By the way, another question : my silencer exhaust are shorter than stock ones (17" compare to 25" i think) i know that the total length of the exhaust can influence the tune up of the carbs.
--> Is that right ?
--> If yes, to your opinion, should i find the correct air/fuel ratio up or down the 3/4 turns ?
Using different silencers may well result in a weaker mixture due to a reduction in back pressure and reflected pulses so it's something to check at high revs/load but it's not likely to have much impact on the idle mixture settings.
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oK thanks I have a Carbtune to try to adjust the carbs as good as possible. I will try !
Guyom
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Although the enricheners are installed correctly and mechanically functional, that bit of fuel from those mini carburetors has to get into the Bing's throat. If that's not happening, it might be time for a thorough cleaning of all the fuel passages within the carb bodies.
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Hi guys l'm a bit confusing... I reset my carb, but clearly when chokes on, motor starts caughing and stops. RPM inscreases a bit at the beggining of the choke and after the motor stops. When the choke is full on, no way to start the motor without a bit of gaz, otherwise, it stops !
I also saw another problem : to have the same RPM level at baseline when the motor is hot, sometime it's low, around 800-1000', and the next stop, at neutal position, it,s 2000 RPM. I put the fist gear and then the RPM decreases at normal 800-1000). Is it possible that my clutch is not correct ?
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To be blunt the enricher on a Bing Carb is a relatively crude device and some work better than others. If you need to use full enrichment to start the engine you should reduce the amount of enrichment immediately. There is no way the engine will run on full enrichment except perhaps in the middle of winter. Also you can't necessarily expect the engine to idle with the enricher on or with it off until the engine has warmed up. Basically use the minimum enrichment needed and turn it off as soon as the engine runs without it but don't expect the engine to idle until you have ridden a few miles.
The high revs problem. Are you saying it's 2000 RPM in neutral and 1000 RPM with the clutch pulled in ? If so that may well indicate the clutch is dragging and needs adjustment.
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ok so mine does not work well. but as you said perhaps in the middle of Winter, in Quebec, we have good winter ;-)
For the RPM problem : another road test looks better than the first one... at neutral, RPM looks more stable (around 1000) but something, they were high 2000 and to decrease them, i put the first gear, then release the clutch a bit and the RPM decrease to 1000. Then i put the neutral and that's ok (1000). So the clutch ?
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Again : other remark on my tuning : when i accelerate, middle RPM are low and then increase... I joint a draw ;-). Do you have any idea why ?