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Thread: R75/5 Leaking Carburetor & ON/OFF Clutch Issues (Please Help)

  1. #16
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    I found EUBMW (www.eubmw.com) has good prices for 32mm Bing rebuild kits. The float plate pin is driven out on the side w/out the knurling. The knurling keeps the pin in the body.

    Generally, I found tapping the pin using a plastic screwdriver handle is enough - where the screwdriver is used like a punch while holding the carburetor body in your hand. Another option is to use some channel lock pliers opened wide to squeeze the pin out of the body. The pin is brass and the carb body aluminum, so minimum force is needed.

    I had an occasional carburetor flooding problem with a Bing alcohol proof float kit installed. The problem was varnish from sitting 16 years caused the floats to stick when the float bowl was low on gas. The varnish still remained even after soaking in carb cleaner. Polishing using Brasso and pipe cleaners solved the problem.

    Fuel bowl overflowing suddenly occurring is caused by: the float sticking or sinking (i.e. bad or sticky floats), the needle valve damaged or deteriorated, or debris at the seat preventing sealing. The easiest to check is debris at the seat which often leaves residue at the bottom of the float bowl, next is removing the needle valve and inspecting the needle valve and carb body seat, finally the floats can be checked for their buoyancy in gasoline (which is messy and unpleasant). I think most people just replace the floats rather than test them if they are the most likely problem. Good Luck!
    Stan

    AH# 13238

  2. #17
    Registered User mt4jim's Avatar
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    I have had leaking "float bowls" that were really just old fuel lines that were cracked. Or..Were not sealing due to clamps that were too tight. Or...(Lots of reasons).

    Hard to tell if the leak travels down the line to the outside of the float bowl. Looks just like the float gasket is leaking.

    I and some Airhead friends (more knowledgeable than I) have spend countless hours trying to diagnose float levels when it turned out that the lines were somehow leaking. Or the gaskets not sealing.

    When the woven fabric lines get old they seep...Look for wet lines if you have these. Will often start out seeping (after sitting for a long time) and then seal once they are "seasoned" with fuel.

    Hope this helps

  3. #18
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    Quote Originally Posted by JETHRIDGE View Post
    Ref overflowing carb. To check the fuel depth in the float turn the gas on then turn it off when the bowel has filled. Disconect the fuel line at the CARB, otherwise you will get the gas in the line in the float bowel. Lifting the float with your hand is not a good test as you put more pressure on it than the gas. Done that and gas shut off yet overflowed when bowel reinstalled. Fuel depth 1/2 inch from top of the bowel is a good test. Now, clean the needle seat with a Q tip and Brasso. Install NAPA in line filters. Checking the floats as said is good to do. I piesce of wire holding both floats up should give you an indication that the floats float the same. Bending the tabs to adjust the floats should not be needed as there is nothing that changed to floats unless they don't float right.

    Sorry but Its kind of hard to understand everything your saying. Could you please clarify?

  4. #19
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    Ok, so I went tonight to try to adjust the clutch by the BMW Tech day spec that was mentioned in this thread and found out something a bit wierd....



    I used a 201mm (8inches approximately) piece of straight coat hanger and no matter what i could not get the clutch arm and clutch cable end (at transmission side) to come close to this measurement. It was pretty far away from the end of the clutch cable bead.


    Any idea why this is? I took the handlebar adjustment as far out as I could (probably 7-8 threads possibly more) and was still far off.


    Another thing I noticed is that there was considerable up and down play on the clutch lever (which according to snowburn is not good). What needs to be done to remedy this issue as well?


    Is this essentially an issue with the clutch cable just being old? If so I will go ahead and install a new clutch cable tomorrow evening I think.

  5. #20
    Administrator 20774's Avatar
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    Sounds like you may have the wrong cable...I would get a new one just to answer that question plus it will be smoother in operation. I recommend BMW cables...some aftermarket seller cables I've tried are not nearly the same. Some people make their own cables, but I don't know how to do that.

    As for the lever, on my /7 there is a plastic or nylon insert called a bush (#3) that was worn out:

    http://www.realoem.com/bmw/showparts...51&hg=32&fg=72

    Interestingly, I don't see that on the R75/5:

    http://www.realoem.com/bmw/showparts...50&hg=32&fg=72

    If there is no such bushing for you model, then it's likely that the parts are just worn out and may require both the handle itself or possibly the part secured to the handlebar needs replacing. The handle would be far easier of course.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  6. #21
    Registered User rapz's Avatar
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    I had both those issues on my '79 RT. I fixed the carb problem by installing some inexpensive fuel line filters from Auto Zone. The clutch sticking was from lack of use. Just ride the heck out of it. I have both issues covered on my blog if you'd like to check it out.
    Website: www.airheadmoto.com
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    Current Bike 1979 BMW 100RT; 2013 BMW R1200RT 90th Anniversary Edition; 2008 Harley Davidson Ultra Classic 105th Anniversary Edition

  7. #22
    #4869 DennisDarrow's Avatar
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    3' of braided fuel line from a VW dealer or a BMW mc parts dealer will be good for several years of service, with quite a bit left over for replacement of those bits that typically develop leaks The most time consuming line is the one through the air filter housing. Yes, one has more leaks because of the fuel lines than any other reason. In line filters just below each petcock should be standard on ALL gasoline engines.

    I go through a lot of 5 gallon cans of gas here on my place with log splitter, tiller, branch chipper, chain saws, leaf blowers, and generators going through perhaps 5 gallons every other week or more. When I empty a can, plastic now adays with the hated flow inhibitor, I always look down inside to check out the debris......Almost ALWAYS there will be crud down inside. This for me, comes from the place where I get my fuel as I take care to keep the nozzle and filter funnels clean.............Diesel is even worse as there will ALWAYS be globs of dark brown gunk floating in the bottom...........THIS IS WHY I use Stabil or an enzyme product and Lucas fuel treatment in my storage gasoline. Each machine except the blowers and chain saws have an inline fuel filter.........Actually, the chain saws and blowers have filters down in the tank from the manufacturer...........

    Surely not to start some kind of gasoline thread but passing along an observation that totally effects our MC's especially this time of year when we put them away for who knows how long between rides........

    Didn't the /5's have a wavy washer there in the clutch and brake handles that helped take the "slop" out of they way they fit??? Been awhile since my /5 days but somethin back in the ol memory that is left seems to strike a bell......I f so would be surely easy to loose .......God bless......Dennis

  8. #23
    Registered User lmo1131's Avatar
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    Didn't the /5's have a wavy washer there in the clutch and brake handles that helped take the "slop" out of they way they fit???
    Excellent recall Dennis. #17



    And yes, it was very easy to lose.. .. .

    "It is what you discover, after you know it all, that counts." _ John Wooden

    Lew Morris
    1973 R75/5 - original owner

  9. #24
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    Aha! Ok. Ill be ordering a new one of these.


    Out of curiosity, should I grease the clutch lever or anything of the sort maintenance wise?

    I was reading Duane Aushermans page but didnt see any mention of it.

    Oddly enough I have heard numerous people mention they had a nylon bushing in their lever. But yeah juding from the parts diagram it doesnt seem like the r75/5 has them.

    As for grease on the clutch bushing thing/etc... what is best to use? Ill need to pick some up from an auto parts store.

  10. #25
    #4869 DennisDarrow's Avatar
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    [QUOTE=jbf;839073]Oddly enough I have heard numerous people mention they had a nylon bushing in their lever. But yeah juding from the parts diagram it doesnt seem like the r75/5 has them.

    QUOTE]

    As with many other forums, thread count does NOT equal credibility. Nuff said

    Yes, you do need to put a dab of grease on the small union where the cable joins the lever and on where that part pivots in the grip housing. Other than that perhaps some PB Blaster on the handle/housing pivot point. Yes, from time to time some electical contact cleaner into your switch............Plain ol grease works just fine of this job........God bless........Dennis

  11. #26
    Monza Blue 1974 R90/6
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    My /6 has a nylon bushing in the lever pivot hole that can be replaced.

    Barron

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