Fellow Inmates, help a newbie get his bike running good, pleasssee.

Discussion in 'Airheads' started by Yachtie, Nov 1, 2012.

  1. disston

    disston ShadeTreeExpert

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    The swapping the carbs trick is a good one but before you do that look in the fuel bowls. There is a wire holding the fuel bowl on the bottom of the carb, each carb. This is called a bail wire (or maybe it's a bale wire). You push the bale wire with a finger, or a screwdriver handle if it's really tight, to one side, it will only go one way and carefully drop the fuel bowl. If there is water in the gas it will be under the gas and you will be able to see it. The water does not mix with the gas. If only gas in in the bowl you can dump this back in the tank. and continue looking for problems.

    You say that you have put new Bosch coils on the bike. Are these the correct 6 volt coils? Where did you get them?

    Most parts for Airhead motorcycles are available at some BMW motorcycle dealers. Do you have an Airhead friendly BMW motorcycle dealer near you? Tell us where you live we may be able to suggest somebody or otherwise you will be having to use the postal service and internet ordering.

    Start making a list you will be having to make an order soon. Put the rubber tubes from the carbs to the heads on your list. You may end up getting complete gasket kits for the carbs or just a few of the pieces but right now you are taking the float bowls off so look at the gasket on the carb body that the floart bowl contacts.

    So far all you have needed in the way of tools is a couple of metric wrenches and a screwdriver. Start a list of the tools you will be needing. You can get an idea of what tools you'll need from watching the tool kit auctions on Ebay but those too kits are always over priced and few of them are complete. You don't need German wrenches to work on your bike but you may pick up a few. Craftsman Tools from Sears will work fine. Common wrenches needed are 8mm, 10mm, 12mm (need two), 13mm, 17mm, 19mm and 22mm. I'm pretty sure you don't ever need a 15mm or a 16mm, I'm not sure about 14mm. There is a use for a 24mm wrench but you may not need it right away.

    There are 5 hex key wrenches in the tool kit. Sometimes called Allen wrenches. You need 3mm, 4mm, 5mm, 6mm and 8mm. I really for the life of me don't know what the 3mm one is for but it's in the kit. A metric assortment of Hex Keys will have these sizes and more. You may get by with one of the hex key sets in a holder that keeps the all together and makes it easy to not lose one or two but if you lose any you will lose them all, you know the type I mean. I don't care for those but they are sometimes handy to have and they may be all you find some places.

    There is a common convertible screwdriver sold in most hardware stores I like. It has interchangeable bits, two sizes for flat and two sizes for Phillips. These seem to fill the bill I think but I usually have others also.

    I hope that gets you started.
    #21
  2. disston

    disston ShadeTreeExpert

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    One more note about Hex Keys. Cheap ones are just that and they will not last. They may also damage fasteners and be in more ways than one counter productive. The German Heyco Hex Keys in the OEM tool kit are a quality item. In fact cheap tools in general are not a good idea. There are cheap brands but quality too so try not to get stuff just based on what it costs. As a general rule Craftsman is OK. Snap On and Mac are the best but they cost too much.
    #22
  3. chollo9

    chollo9 Screwed the Pooch

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    Maybe I missed something, but I read, "Installed new ignition." and also, "Haven't done anything about timing." (not exact quotes).

    "Close" timing can "work" at low engine speeds and temps, but once things speed up and heat up, not so much.

    Not familiar with Enduralast's ignition, does it provide for individual cylinder timing?

    I might be way off, but that wouldn't be anything new . . .
    #23
  4. Yachtie

    Yachtie Been here awhile

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    My friend who installed the Electronic ignition says it did the timing per spec. " I haven't done anything with the carbs" as of yet.
    #24
  5. Yachtie

    Yachtie Been here awhile

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    yes, new bosch coils from Euroelectric, same place i bought the charging/ignition systems.

    Thanks for all the great help! I'm going to do the fuel bowl tonight. If it were water in the fuel wouldnt it be acting up on both cylinders? The problem only exists in the right cylinder. Left seems and acts fine.
    #25
  6. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    All good advice, but I would consider swapping the carbs left to right a last resort, the valves and timing should be checked first just to establish a baseline before messing with the carbs. The right carb also has the oil from the breather dumped into it, did you compare the spark plugs? Wet, black and oil fouled plugs could cause missing. If the fuel lines are getting old they can also shed small bits of black rubber which can block jets and/or jam intake jets. Lastly, once the basics are covered, you could try slowly adjusting the mixture screw on the bottom of the carb while the bike is running (not the idle adjustment screw on the side of the carb) If the air filters have more or less flow than stock it can affect how much fuel the carb pulls.
    #26
  7. mykill

    mykill odd

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    Does it idle on both cylinders? Then bog when you accelerate?
    I would go back and check everything your sausage fingers touched and double check the settings..
    #27
  8. Yachtie

    Yachtie Been here awhile

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    I would say the bike idles fine. bogs when you rev/accelerate but once warm its bogs with even the slightest acceleration.

    For someone who has never adjusted timing is there a "valve timing for dummies" Thread out there preferably with pics?. Think someone posted one already just haven't had time to look at it yet.
    #28
  9. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    Do you have a strobe timing light? They are easier and more accurate than the old bulb and a wire type. If so, hook it to the batteries pos and neg, clip the third wire to the sparkplug wire and aim at the timing hole. Idle should show "S" mark in window, revs to 3000 rpm should show "F" mark centered in window. All this is moot if you have dual plugged heads which require less advance.
    #29
  10. spo123

    spo123 Man About Town

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    Perhaps the plug wire CONNECTOR(s) at the plug?
    #30
  11. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    Yes, or it's loose at the coil end...
    #31
  12. batoutoflahonda

    batoutoflahonda Long timer

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    Whoa. back the bus up people. So a bike in an unknown state of tune with a bunch of new stuff on it?

    1) Check the valves
    2) Set the timing
    4) Take it out. Get it good and warmed up, then sync the carbs and set the idle. If Idle is off after adjustment, re-time it.
    5) Report back

    You need a base line. As mentioned earlier.
    #32
  13. spo123

    spo123 Man About Town

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    If the valves are adjusted correctly AND the timing is correct, it may NOT be possible for a proper warm up ride......IF spark to the plugs is ERRATIC.
    FYI....as I previously stated.......double check all electrical connections (in IGNITION SYSTEM)......use an ohm meter to test the PLUG CAPS....
    The ORIGINAL METAL CAPS are known to FAIL and pass no ohms....ie: infinite resistance.
    Replacement NGK BRAND caps are INEXPENSIVE.......There IS a difference of ohms for POINTS and for ELECTRONIC ignitions.....YOU may look that up....it is easy to find.
    Best wishes always!

    spo
    #33
  14. photorider

    photorider Been here awhile

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    I agree with spo123. It has to be a bad connection. My money is on the electronic ignition. Which one did you install? I'm going to go out on a limb and guess Dyna III (because it's the one I have experience with!). Seriously, I've experienced VERY similar behavior with my /6. Both times, it was a loose sensor plate. It started, ran, idled, everything was fine, until it warmed up. Then, the connection started to fail and it would run only on one cylinder. The install instructions warned about over tightening it so I was too gentle with it and the motor's vibrations made it loosen over time. Do yourself and before you start throwing more money at it, just look under the front cover and make sure the little round sensor plate is making good contact with the case. That is how the system is grounded and a clean, snug connection there is imperative. No need to tighten the shit out of it, just make sure it's good and snug. If that doesn't do it, then go to the spark plug wires. If they are the original ones, they should be replaced anyway and, as previously stated, they are not expensive (especially if you make them yourself). Good luck!
    #34
  15. Yachtie

    Yachtie Been here awhile

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    So i'm in the process of doing the valve clearance.

    The valve clearance was sooo tight on the left side. Took like 3-4 full turns on the bolt to get the feelers through. Using .15mm on the intake .20mm on the exhaust.

    But now the rocker arm as back and forth play, the 4 nuts are tight to 25lbs.

    I was using this as a guide
    http://w6rec.com/duane/bmw/valve/index.htm

    he said before doing valve clearance to make sure the rocker arm didnt budge (correct if wrong) and it didnt so i proceeded to valve clearance. Now there is play as stated now that the clearance is right.

    I buttoned everything back up and fired the bike up for a minute. I can hear valve noise now and he said i would if it was not tight. Positive side was after 2 pulls of the throttle the caughing seems to be gone. But I shut it right down when i heard the ticking in the valves.

    Could someone explain how to get rid of this? his instructions say tighten the nuts but they are tight... I may have missed something though...

    have this ignition installed
    http://www.euromotoelectrics.com/EnDuraSpark-Electronic-Ignition-System-BMW-R-70-95-p/edl-ign.htm
    #35
  16. Big Bamboo

    Big Bamboo Aircooled & Sunbaked

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    It sounds to me like you may have adjusted the wrong valves. There is no way it should have taken that many turns to achieve the right clearance. Which method are you using to turn the engine to top dead center? Better yet, you can call me at Eight 0 Eight 8 Eight 7 Two Zero 2 Seven and I will run you through the procedure. Typing it all out takes too long...
    #36
  17. disston

    disston ShadeTreeExpert

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    Try to be careful with language, some of the things you say aren't very clear, but I understand if you are new to this the language is new also.

    You say the rockers have back and forth motion? I think you mean vertical because they are not tight enough between the blocks? You are going to need a torque wrench set for 25 foot/pounds. When you have both rockers loose and one side is ready for adjusting the valve lash you can loosen the two nuts holding the intake or the exhaust rocker and squeeze the blocks together. Hand pressure should work on a /6 but some find the need a little more pressure from a set up of sockets (to clear the rocker shaft) squeezed by a large C-clamp or large pair of pliers. Do one at a time either intake r exhaust then do the other. This way you will not have to tighten the nuts down in a stepped pattern like was done when the gasket was new because you have only two nuts loose at a time.

    There are a couple of ways to determine which side is ready for adjustment. If you have both valve covers off and set the flywheel to top dead center then one cylinder will have both rockers loose. This side, which ever it is, is at TDC. The other side is also at TDC but on the exhaust stroke. After setting one side spin the crank, with what ever method you use, 360* and it will be at TDC again only on the other cylinder. To say another way, when the bike is at TDC one side will be ready to adjust, this side should have loose rockers, both. The other side is 360* around.

    I guess it may be possible to have a valve that tight. But I agree with Mr Bamboo it doesn't seem likely. That's why we think you adjusted the valves on the wrong side.

    Moving right along. The other method of determining which side to set may be instructive. Take the valve cover off one side, I usually start on the left side. I use the Hex Key in the alternator bolt to rotate the engine and watch the window for the TDC mark and at the same time watch the valves, particularly the intake valve. Right after the intake closes is when the TDC for that side will appear. So I watch for the intake closing and as soon as it does I watch, it'll be pretty soon but not right away, the TDC mark. TDC. Then to find TDC on the right side I only have to rotate the crank 360*.

    There should be very little to no vertical movement of the rockers. There will almost always be some valve tapping noise. And the clutch linkage in the trans also rattles in neutral. Just be thankful most of these motors don't have the Turkey Gobble Valve any more, most have been changed out by now. But if you get this thing running and you hear a Turkey Gobble noise when sitting at a stop light we have a fix for that too.
    #37
  18. disston

    disston ShadeTreeExpert

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    When you are trying to adjust the valves you will have to rotate the engine either by a Hex Key in the alternator bolt with the engine in neutral, or the engine in gear, higher gear works better, and rotating the rear wheel. Which ever method is used remove both spark plugs so you aren't rotating against engine compression.

    I know you are keeping your eyes out for some loose wire, dirty connector, solution to this problem But in the mean time we would like you to put the bike in a state of basic good tune. It's been said before, (1) set the valves, (2) Adjust the timing, (3) adjust carbs on a warmed up engine.

    So far we have said a lot about adjusting the valves. This is a critical adjustment for you to get right and to get it right it must be done right. So I hope you get this part. For timing adjustment you will need a timing light and know how to use it. Have you got the timing light? And the know how?

    And for the 3rd thing I'm going to give you the basic settings for this engine and the carbs on this engine so it will run after you have done the other two things. The carbs on a 1976 R90/6 are the Bing 64/32/11 & 12. I don't think at this point we are suspecting any problems inside the carbs like plugged jets or bad/maladjusted floats? What you need is the basic setting for these carbs that will make the bike run well enough to get it warmed up. This follows;

    There are two screw adjustments on the underside of the carbs. If you are not working on a bike stand but the bike is on the ground you will have to lay on your back on the ground to see these screws. The smaller screw that is inside a shrouded part of the carb body is the mixture screw. For this bike the mixture screw is one turn out. Turn the screw in gently till it seats. Do not turn the screw in tightly. It can be damaged or, because the screw is steel and the seat is Aluminum or Brass, the seat can be damaged. Turn the screw out some and in several times but don't seat it too tight. Then after you have found bottom turn this screw out One (1) Turn. This is the basic setting for these carbs on an R90/6. Other years and other carbs may have a different setting so if your buddy with an R80 G/S tells you he uses a different setting don't worry. Different bikes, years, carbs, different basic settings. I get this information from the Bing manual.

    The other screw on the bottom of the carb is the idle speed screw. It is larger. It has a spring around it, that you can see, the mix screw also has a spring on it but it's inside and not visible. The idle speed screw opens the throttle butterfly, but just a little, to allow the engine to idle. It is really hard to see with the carbs on the engine but the idle speed screw should be about one turn in from the point it first contacts the lever it pushes against. I get this setting from an old friend of mine, it's not in the book.

    If no other problems with the carbs this will allow you to ride enough to warm the engine and then be able to properly balance the carbs. We will maybe have to do another whole couple of pages on balancing but I think that can wait till you report back on progress.
    #38
  19. Yachtie

    Yachtie Been here awhile

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    well....

    After a few calls to Tim (Big Bamboo) i think i sorted out the valve clearance. but i'm still hearing a valve ticking that to me seems too loud, Tim said you should hear something but i think its too loud which has me think i've done something wrong.

    but the bike started up and for the first 20 minutes ran great, no problems, then as soon as the engine warmed up it started stumbling/coughing/back firing again.... sucks.... was hoping to fix the issue...

    Also checked both fuel bowls and they both had nothing but clean clear fuel in them.

    What should i try next?

    I did say in previous posts that it only seamed to be happening on the right side but today it was both and very well could have been both the last time we checked. So lets just assume its always been both from the beginning.
    #39
  20. disston

    disston ShadeTreeExpert

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    Set the carb mixture screws to one turn out. This is the basic starting setting for your bike in the Bing manual. Further directions and explanations are in my two posts above which I made when you were on the phone with Tim.
    #40