Carb rebuild and other stuff - "Newbie with a pig"

[DerekM]

Nice duderinos.

Carby questions. Torn rubber bit and crusty needle, replace them? Also how does the needle come out?

[Mike V]

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.

[DerekM]

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.

[Bob_W]

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

[montmil]

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.

[DerekM]

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?  :-?

[montmil]

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...

[DerekM]

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.

[montmil]

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.  

[DerekM]

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?

[Luca]

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.

[Mike V]

...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.

[livingdeadhead]

and your centre stand needs work too! mind you we've all been there! lol

[DerekM]

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!

[DerekM]

It always gets uglier before it gets better.