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Comprehensive carb kits

Bruce Suehr
(@bruce-suehr)
Active Member

Hey all, I'm beginning work on a1973 R75/5 .  Bike's sat a long time. I've removed the tank and am using the POR15 system to clean and seal. I have both petcocks apart and ready to rebuild. I've removed the carbs from the bike today ( 64/32/9 and 10). The gentleman that I bought the bike from had rebuild kits but I am concerned after reading Snowbums articles and others that I'd be making a mistake using a $10 rebuild kit. Can someone tell me where I should source a comprehensive, quality rebuild kit?  I want to replace every part on the carbs. Motobins, euromotoelectrics, boxer2 valve, bob's???Thank you in advance

Quote
Topic starter Posted : 04/10/2022 14:20
Richard Whatley
(@wobbly)
Member Moderator

I rebuild cabs all the time without "replacing every part". Generally I get my parts from Bob's or from Bing, the problem being that original parts are bought by the piece. I don't recall ever seeing a "Bing kit". The one exception is a 10 or 12 pack of float bowl gaskets because that's one part you will need to keep on hand.

There are some parts that should be replaced for various reasons...

  • Needle - The needle sees wear due to sliding in and out of the needle jet
  • Needle Jet - The jet gets hammered oversize due to the intake pulse
  • Pilot Jet - First to clog and hardest to clean without enlarging the metering orifice
  • Float - Bing issued revised Ethanol-proof parts in the 1990's
  • Float Needle - Good float system sealing is imperative
  • All O-rings - All neoprene parts harden with age
  • Diaphragm - Always check for holes and slits. Replace if needed.

It is also advisable to...

  • Replace the head-to-carb intake hose every 10 years due to hardening of the rubber. This also affords a chance to check the tightness of the screw-in intake spigot in the cyl head.
  • Check the air filter while the carbs are off. Clogged air filters will enrichen the mixture, which can be hard to diagnose. Clogging can come from faulty breather hoses in the starter motor compartment leaking an oil mist, or from mice wintering in that space and building nests that clog the entire intake air track.
  • Check for equal extension of the Needle on both side. Since the Bing doesn't allow you to see the actual needle clip, it is easy to get the needles installed at different exposed lengths.

Hope this helps.

[color=blue]Don't hide 'em, Ride 'em !!
#15150[/color]

ReplyQuote
Posted : 04/11/2022 05:15
Bob Whigham
(@1872)
Estimable Member

Bing sells kits, 1-7 with 7 being the most complete: 2 floats, pivot pin, float needles, jet needles, needle jets, diaphragms, gaskets and o rings. Call with your carb number and while at it get a Bing carb book, about $12.00. Everything you probably ever want to know about Bings and then some. The alcohol resistant independent float kit  with new bowl is not recommended. Others may sell the same kits. 

ReplyQuote
Posted : 04/11/2022 11:10
Scot Marburger
(@8166)
Member Moderator

First, get the Bing book, as it provides lots of good carb info.

Not sure it's still the case, but buying the parts from your BMW dealer usta save you some money. Look up your bike at realoem.com and you'll find all the jet, needles, o-rings, floats, gaskets etc. part numbers, or just go down to the dealer and see if their parts person will look them up for you.

With a pair of carbs with which I have no familiarity, I like to replace ALL the o-rings, including those on the butterfly shaft, the floats, the needle jets, needles, and the float needles. I order new enrichener and float bowl gaskets, too. Not cheap, but you'll have a known good basis to work from when I'm done.

Tech articles on rebuilding the Bing carbs can be found on this site.

Good luck, and please follow up with us with how it worked out for you, OK?

ReplyQuote
Posted : 04/16/2022 13:04
Bruce Suehr
(@bruce-suehr)
Active Member

Carb rebuild went great thanks largely to all of your help. The only question I have is where in the heck does the toothed washer go?  Small black toothed washer I got from euromotoelectrics. I found an exploded diagram that shows it going into the top of the slide over the clip that hold the slide needle. Not sure if it's a captive part or what. Anyway, thanks for your help. Closing in on an initial startup. 

ReplyQuote
Topic starter Posted : 05/13/2022 18:01

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