The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: DerekM on March 31, 2014, 09:05:10 PM
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Nice duderinos.
Carby questions. Torn rubber bit and crusty needle, replace them? Also how does the needle come out?
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Derek,
Looks like a complete rebuild is in order. Yes, replace the needles, and the needle jet too. New diaphragms, gaskets, O-rings, float and float needle may be a good idea also.
http://www.bingcarburetor.com/bmw/cvexplode.html
To replace the needle, grasp it firmly between your fingers, turn 90° and pull down. Depending on which notch the needle is on you may have to do this 1 or 2 more times. The needle is held in place with a clip fixed in the slide. The needle has a series of staggered alternating notches. refer to the above link, page 1, #4 of the schematic.
A few pictures that may help...
http://tinyurl.com/kz3sekl
http://www.pt-photos.com/carb_page.htm
http://www.youtube.com/watch?v=Q__LkgoaGGk
http://www.youtube.com/watch?v=4TiI18uNjR4
You may think about doing a complete rebuild of the carbs, soaking them in a solvent/carb cleaner of your choice. Carefully clearing all the orifices, rinsing and blowing dry. Carb kits can be obtained from many airhead vendors. If you're not familiar with the CV carbs - just ask in the Technical Q&A section here. You'll get plenty of good help from a lot of experienced folks.
No dumb questions here. If you're not sure - ask. You'll get plenty of help and direction here.
-Mike V.
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Gracias for the links!
I've got a bucket o' cleaner and a couple cans. so I'll do an inventory and put a parts order in. Saw a link for $30 rebuild kit w/diaphragms, so I'll order the parts when I make a full list. Got the manual from the previous owner so that will help with things too. The carb is really similar to the modern lambretta carbs so I think I can do the rebuild and have a friend who can help tune/sync them when it gets there.
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Bing carb book is about $12.00 including shipping. It has information on jet sizes for all models, operation and troubleshooting fuel circuits. It was helpful to me.
Bing Agency in the US
Bob
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Personally, I would question the $30.00 diaphragm rebuild kit. If it's an off-brand, off-shore vendor, you may be getting diaphragms of unknown quality which could very well lead you down a rabbit hole in a quest for a good running engine.
Before pulling the needles from the slides, take an accurate measurement as to how far out the needle extends from your slide reference point. Measure both needles as some owners have reported finding one needle at a different length than the other. Record this info. It may be helpful during the refit but, with the neglected condition of your project, you'd be better off refitting the needles in the correct notch as dictated by the carb's model number specific to your R65's vintage.
Should you elect to remove the butterfly and its shaft and o-rings, upon refit, pay very close attention to the two small brass screws and the exact position of the butterfly within the carb body. Any misalignment and contact with the body will drastically effect operations.
Note that the enricheners are 'handed' -there's a left and a right side assembly- so do not mix parts.
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Fair point. I've learnt that lesson before and would rather not go down that path. here was the link I was referring to:
http://www.eubmw.com/Carb.html
I do not know anything about order parts/dealers/reputation etc. so any tidbits would be appreciate, even if its as simple as "you get what you pay for."
Using max's BMW parts online the total starts looking like $175 - $200 to rebuild these things? :-?
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Derek, I've shopped with EUBMW before and the guy is straight up. His price for the stated Bing-component rebuild kit is per carb so you're looking at $60.00 for the soft parts. That's still below dealer offerings that bounce around $70.00.
Your pretty much on the mark for the total cash outlay for rebuilding both 32mm Bings. When ordering carb bits, be sure to include the carb's model number that's found on the carb body. You might want to check and confirm that your Bings are the same series. PO's sometimes do strange things...
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Awesome thanks, i'll confirm the carbs and the month/year of the bike.
I just called EUBMW and the carb kits with diaphragms are for 2 carbs, so its a substantial savings then.
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Awesome thanks, i'll confirm the carbs and the month/year of the bike.
I just called EUBMW and the carb kits with diaphragms are for 2 carbs, so its a substantial savings then.
That is remarkable; especially if it's as you've stated on the price. I'd be just suspicious enough to inquire if they are genuine Bing diaphragms. Perhaps call back and ask for confirmation that the diaphragms are actual Bing products from BingUSA and not repops.
Or call Bing and ask if EUBMW is selling their products or repops. Old saying... Trust but verify.
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Turns out the bike is an 81.
Started tearing into the other carb tonight. had to extract a screw from the cover and when i opened the top the diaphragm was way out of place. Ripped the diaphragm out and the slide is stuck. i've tried PB blaster and some heat, and vice grips but no dice yet. any advice would be helpful.
also on the to-do list. Front brake reservoir was filled with mud. Cleaned out a bit but need to make sure its cleaned up and i get new brake lines.
I need to replace the key switch, but a screwdriver does the trick right now.
And does the stand look okay?
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You could try spraying your penetrating oil through the holes in the bottom of the slide. Fill the whole thing up and let it sit. Maybe put it under a 100W light bulb (incandescent) to give it a constant, gentle heat. Also, I'd suggest tapping with a plastic hammer, not grabbing the slide with vice grips. Put a lateral force on it rather than trying to pull the slide straight out.
I remember when I was dealing with a frozen trip meter a member here suggested soaking the parts in vinegar to loosen the rust. You could try that too. Not sure how that will work or behave with the aluminium, but I think it's worth looking into if the penetrating oil doesn't work. Either way you go, patience will be your friend.
Being an '81 doesn't change much for your bike, although that round master cylinder reservoir is supposedly not removable from the master cylinder bore. The later rectangular ones are, and thus better IMO. Seeing your pictures of the reservoir, I'd have a look inside the MC bore itself. Could be a good amount of pitting in there. New ones aren't cheap, but not outrageous either. You could probably source a used one online. Pay attention to the bore size if you replace or repair, there are several different MC sizes available for your bike.
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...patience will be your friend
Valuable advice from Luca.
50/50 solution of Acetone and Automatic Transmission Fluid makes for a powerful brew. Good to see another resurrection in the making.
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and your centre stand needs work too! mind you we've all been there! lol
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and your centre stand needs work too! mind you we've all been there! lol
I've been looking at it wondering if I need to inspect further. Thanks!
Got the carb bits from EUBMW, definitely 1 kit for both carbs. Sourced a new slide thanks to rick m. in inglewood. Great resource to have!
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It always gets uglier before it gets better. ;D
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[movedhere] General Announcements [move by] Justin B..
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Noticed the worlds tiniest grub screw on the table while starting the carb rebuild. Does this go with a 32mm cv carb, it's not in the diagram. Atomizer for scale.
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I don't recognize that from the numerous times I've taken my carbs apart. :-?
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Sure is small. I don't believe Bing CV's have such a thing.
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I see you've found the $3000 grub screw ;D
But seriously, I don't think I've seen one of those anywhere on the entire bike. Are the threads metric?
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Got the carbs rebuilt but not getting any fuel into the cylinder, I can get a rough start with throttle open and starter fluid but I'm going to run through the carbs again and double check everything. :P
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Sounds like idle circuit problems. The small passageways for the idle jet and idle mixture are easy to clog, and compressed air/carb cleaner spray don't always clear them.
I took an old high E string from one of my guitars and cut it about 5" from the bottom end, which has a nice brass barrel on it for easy handling and locating. Have used that for poking out passageways. Yes, steel strings could potentially score the carb bodies... just be gentle.
Might be worthwhile to make sure the enrichener discs are also installed correctly and clear of blockages.
Congrats on getting the bike to cough and sputter. First breaths are always a promising sign.
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Didn't we just solve this very same problem within a similar thread? Derek, have you checked the Tech section for similar topic? The answer is there.
There are a couple tiny holes just under and very near to the butterfly. If these are clogged, no atomized fuel will pass thru the starting fuel circuit and the bike will not start. Have you confirmed these passages as being clear? Single piece of way thin copper wire will work as a probe.
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Gone through the carby and turns out the spring was missing off one of the idle screws, along with the plugged holes.
Got it running tonight, albeit rough and smokey from the exhaust like crazy. Starts up by covering the carb intake with my hand and it runs with the choke at 1500 rpms or so and climbs up to 3k without. So there is definitely an air leak and tuning to do. I don't have an exhaust wrench to use so hopefully the exhaust clears itself out after a couple rounds.
I like progress. Progress is good.
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Its definitely progress.
Keep on with it.
Cheers
Rev Light
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If the enrichener circuits are clear and both enricheners assembled correctly, and all air & fuel passages open, you should not need to block the carb's air intake to get an engine start.
The idle speed increase is mostly likely a misadjusted idle screw/s. A complete carb balance is a future job but for right now, try closing down the idle mix screws and see if that does not help reduce the idle rev increase. The engine must be at full operating temperature before beginning carb tweaks. Anything less than completely warmed up is but an exercise in frustration.
Confirm both idle air screws have their o-rings in good condition. Helpful to use just a light touch of plumbers grease or dielectric grease as an aid in preventing those critical o-rings from rolling out of place or being torn.
Keep after it. Once dead, now alive. That's progress. [smiley=thumbup.gif]
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It's starts regularly with the idle screws all the way in and the choke on. It idles badly with the choke on, and races with the choke off as expected.
Loosen the idle screws 1/4 turn or more and it won't start with or without the choke. I think that indicates the idle circuit is blocked right?
I cleared out all passages with a strand of wire, including the idle jet.
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I wouldn't expect it to race with the choke off during the first few minutes of operation. A cold engine should be reluctant to run without the choke, and race a bit while the choke is on, especially as it warms up.
That, combined with the fact that it doesn't want to run with the mixture screws backed out at all (they fatten the mixture going out on CV carbs--opposite of slide carbs) makes me thing the bike is running way too rich. If the smoke in the exhaust is black (black=excess fuel<-->white=burning oil) that would further suggest you have too much fuel.
Here are a few things you can check:
1) make sure the float/fuel bowl levels are ok. Too much fuel in the bowl will richen the mixture.
2) make sure the enrichener discs are not backwards. Pics here: http://bmwmotorcycletech.info/bingcv.htm I'm not sure if having the discs in backwards will make the choke work backwards, but if you have the carbs back off it's easy to check
3) make sure your carb jets are stock.
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Confirm the small brass 'jet' in the bottom of each float bowl is clear. The smaller reservoir feeds the enrichment circuit.
Idle circuit screws must be opened. Begin with the spec's percentage of turn.
Ditto Luca's comments on the enrichener discs, float levels and float needle function.
Confirm correct valve lash and timing. These two items really do effect start and engine ops.
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One other thing, since you've replaced one of the slides, is to make sure the jet needles are the same and in the same position. One needle position change makes a big difference in mixture. I've never worked out how to adjust the jet needle, but you can measure from the base of the slides to the tips of the needles to determine their positions.
Pretty sure somebody around here knows the proper needle protrusion for stock settings.
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Pretty sure somebody around here knows the proper needle protrusion for stock settings.
I've got the measurements for each needle position but I'm away from home until tomorrow. I have posted them before so maybe a search would find them.
Here you go
Needle Position vs Measured Needle Length in mm
1 42.37
2 40.57
3 38.79
4 37.10
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Checked the enricher disks, floats, slide needle, and all the passages and idle jet with a copper wire and still no dice. Jets are correct, but I had the idle screw a half a turn too far out, so I tried to start it up again and no go. Only wants to start with my hand over the carb still, so I think it's getting too much air or not enough fuel.
When I rebuilt the carb I didn't take the butterfly valve out or replace the o-ring on the shaft. If that o-ring is bad or the valve isn't seated perfectly that could be the source of air. Other than that I think replacing the idle jet and screw are the other culprits.
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Slide needle on one side was in the wrong position, used a better caliper to measure it and bingo starts up. Choke makes the idle too high and the idle appears to be a but low. Transitions are choppy too. But it runs. And it will run better after tweaking the carbs!
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Sweet deal! It takes a good 15-20 minutes of riding for these engines to really get up to temp before you synch the carbs, though on a fresh start like this you probably want to try synching them a bit just to make it run more nicely while you warm it up. Poor off idle performance is most likely the throttle cables out of synch--you can get it roughly dialed in by making sure the free play of the cable sheath at the adjustor screw is the same on both sides.
If you still suspect air leaks you can go around with a can of starting fluid and spray it at the boot joints, throttle shaft, etc. Have a fire extinguisher on hand just in case [smiley=thumbup.gif]
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Insure that valve lash is correct and -since you're experiencing temporary running problems- the timing spot on before beginning a carb synch job.
If you get the carbs before the horse, you'll waste your time chasing your own tail.
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A month later, with the bike all back together after greasing the transmission splines, i got to spend some time tuning last night. it runs a ton better, and i've got a buddy with a sync tool that i'll be borrowing for a final proper tuning.