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Thread: Valve clearances

  1. #1
    Rally Rat donkey doctor's Avatar
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    Valve clearances

    Hello; I recently set the valves according to Haynes .008 exhaust and .004 for intake. I noticed that both cylinders were noticably noisier, there was no other symptoms, and to be fair, it was quiet farther up the revs . I thought my engine was unusually quiet, but . . . What do you guys like for valve clearances?

    I should say that it's a 77 R 100/7, 75,000 miles. Otherwise a real sweetheart.

  2. #2
    Loose Cannon flash412's Avatar
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    First of all, you need to make sure that your rocker arms are not what is making the noise through too much lateral play. This is easy to fix. You also need to retorque the four head bolts (after loosening them) before you adjust the valves EVERY time. Finally... in and exh should be at 0.006" and 0.008". BMW changed the spec several times. Tappy valves are happy valves. Maybe yours were too tight.
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  3. #3
    Registered User 88bmwjeff's Avatar
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    My valves were slighlty noiser after I properly adjusted them too. I initially made a mistake and used standard guages instead of mm (grabbed the wrong set). Hope you didn't make the same mistake. Did you take note of the gap before adjusting? It's a good idea to take note of the clearance before adjusting. This will tell you how things are changing. Lastly I was told not to be too worried about hearing the valves-Be more worried if you don't hear them. :-)

  4. #4
    Minnesota Nice! braddog's Avatar
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    Mine too!

    I'd say, normal for the most part. Same thing happened to me, now they're noisy, but they weren't before.
    -----------------------------------------
    Brad D. - Member #105766
    '77 R100RS - Black Beauty (big pipe, baby!)
    '94 R1100RS - Sylvia

  5. #5
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    On older airheads, it's VERY important to set the valves, especially on the R100 models. The original valve seats were designed for leaded gas, and BMW tried several different fixes before coming up with something that worked. The basic problem is that the head castings were designed for a 600cc engine, then carved away for bigger valves as bigger bores were provided. The 1,000 cc engines create a lot of heat and there just isn't enough aluminum in the head to carry away heat from the exhaust valves if you run the engine hard. (I know all this because I had a couple of R100 sidecar outfits that really ate valves)

    The symptoms of tight valves are a very quiet engine, and stalling at idle after a hot, fast run. Clattering valves truly are happy valves, and there is no damage being done. The intakes aren't as critical, and you can run .004 in. if you feel like it. You need to maintain at least .006 in. clearance on the exhausts or they will tighten up and eat the seats. I second the idea of measuring the clearance after a known mileage to see how they are doing. If you can go through .008 clearance in say 2,000 miles, it's time to yank the heads and have the late model seats, valves, and guides installed.

    But, whatever valves you have in your airhead, check and adjust those ex clearances regularly, and especially if they get quiet.

    pmdave.

  6. #6
    Stuff2c
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    Adjust your valves to the factory specs "Often". I run mine tighter than spec because I don't like mine noisey either. If you do them "Often" you can also run them tight. .001 tighter than spec works for me @ 1500-2000 mile intervals. It only takes about 20 minutes to check and adjust mine. Rarely do they all need adjusting and I run in the HIGH Revs.

  7. #7
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by flash412
    You also need to retorque the four head bolts (after loosening them) before you adjust the valves EVERY time.
    You do? Fill me in Flash. As far as I know, they are re-torqued at the first inspection...600 miles.

    What manual is that stated in?

  8. #8
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by donkey doctor
    What do you guys like for valve clearances?
    The usual 0.004" intake and 0.008" exhaust, BUT I add a step.

    I always press down on the rocker arm where it contacts the push rod. This forces any thick-when-cold 20W-50 oil out from between the contact points and provides a more accurate valve clearance. Ie: between the cam and followers, the follower and push rod end and the push rod end and rocker.

    Careful how you press down on the rocker. In a slightly upward or downward direction (I can't remember which) the valve gap actually tightens.

    I've been doing it that way since 1991. Works for me.

  9. #9
    BMWRich58
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    You also need to retorque the four head bolts (after loosening them) before you adjust the valves EVERY time. What manual is that stated in?

    page 2.7 in the BMW Factory Repair Manual for R80-R100R G
    S's. For any valve adjusting and rocker arm adjusting.

    Only I don't loosen and then re-tighten. I just re-tighten/re-torque.


    I always press down on the rocker arm where it contacts the push rod.

    I too, practise this habit.

  10. #10
    Alps Adventurer GlobalRider's Avatar
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    Quote Originally Posted by BMWRich58
    page 2.7 in the BMW Factory Repair Manual for R80-R100R GS's. For any valve adjusting and rocker arm adjusting.

    Only I don't loosen and then re-tighten. I just re-tighten/re-torque.
    Hi Rich,

    I got my BMW Factory Repair Manual on microfiche and printed it out. I always wondered about the actual manual.

    How many pages? How complete? What is the part number on the cover?

    FYI if you try to retorque without loosening, your torque wrench will always show it as meeting spec. You loosen and then retorque in a continuous motion. Stopping motion, and you may not overcome the static friction...same goes for fasteners already close to the torque spec.

    I prefer to just leave my head bolts alone. I check my valve clearances periodically and they hardly ever need adjustment.

  11. #11
    Focused kbasa's Avatar
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    When I had an airhead, I used to loosen the head bolts and then retorque them in two steps, adjusting the rocker endplay during the process. I think I saw it in the Haynes or Clymer manual.
    Dave Swider
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    Some bikes. Some with motors, some without.

  12. #12
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    I try to make a habit of torquing the head bolts (nuts actually) before adjusting the valves. They don't get torqued if I have to adjust on the road somewhere, but in the shop it's so easy that it's foolish to ignore. Stretched studs reduce the pressure on the head gasket, and also allow valve clearance to vary.

    Threaded fasteners sort of "bind" in position, and it's important to loosen the fastener slightly (say a 1/4 turn) just to get the threads broken loose. Typically, I loosen each nut (in a cross pattern) then tighten to almost required torque, then after all have been adjusted I snug them up to the torque. "cross pattern" means not going in a circle, but tightening say, E top, then I lower, then E lower, then I top. I torque the upper and lower head nuts after the main four are done, since they only help compress the head gasket, not hold the cylinders on.

    BTW, if you're experiencing leaks from around the valve cover gasket, it's very likely because the head is warped. Yes, you could disassemble and get the cover contact area resurfaced, but it probably won't be long before the head warps again anyway. I clean the valve cover gasket with brake cleaner, then apply a thin coat of gray silicone (auto) gasket goo, taking care to wipe up any goo from inside the cover so it doesn't get carried away in the oil. I temporarily install the cover, then remove and look for areas where the gasket goo has not contacted and add a little by dabbing with my finger. Then the cover is installed but the nuts are only tightened loosely to allow the gasket goo to set up for an hour or so, then torqued.

    I also drill a small drain hole in the lower valve cover center web to allow water to drip out of the stud area. It helps prevent corrosion of the center stud.

    While we're at it, some folks don't seem to know that the LH and RH valve covers are different. If the covers on your bike seem to slant uphill, they are reversed. For the dense, the clever German engineers have cast a small L or R on the cover.

    I think it would be a great contest to see how quickly you can get the valve covers installed, especially that RH valve cover. And if you can get the RH front nut on too quickly, we could let you do it on a machine with a sidecar attached, to add a little fun.

    pmdave

  13. #13
    BMWRich58
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    Hi Rich,

    I got my BMW Factory Repair Manual on microfiche and printed it out. I always wondered about the actual manual.

    How many pages? How complete? What is the part number on the cover?


    WOW talk about a late reply.....sorrrrrry........

    Part # I believe to be is 01-51-9-799-001

    The manual doesn't exactly have x-amount of pages, but 12 chapters (Roughly 10-30 pages per chapter).
    It is a very good and complete, except you do need a little "experience" in automotive work. I wouldn't say it's very "consumer friendly" like Haynes or Clymer, but is very good and has great diagrams/pictures.

    Be Very Careful ...
    One thing to keep in mind is everything has been "translated" to English. (They use different words that sometimes doesn't make sense).
    And double check all torque values,specifications and quanities. During editing "I believe",some numbers have been mixed up and don't "jive" with the specifications/techanical data at the end of each chapter or at the end of the manual. Like always,double check your work.

    Other than that a great manual!!!

  14. #14
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    Valve Cover Sides???

    While we're at it, some folks don't seem to know that the LH and RH valve covers are different. If the covers on your bike seem to slant uphill, they are reversed. For the dense, the clever German engineers have cast a small L or R on the cover.


    This is a good point. Being new to Airheads I had no idea there was difference. I can't find a "small L or R on my covers.
    The numbers inside my covers are: (1 262 253.1 ) and ( 1 262 254.1 ), original covers, 40years old.

    I have the exact same numbers on a brand-new set of covers I just ordered from MAXBMW.

    Can anyone tell the L/R difference by their part/numbers?

  15. #15
    Liaison 20774's Avatar
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    nevadaslim -

    Those numbers are not part numbers...they are likely mold numbers used internally by BMW to track parts production.

    I don't have pictures of the inside of my /7 valve covers, but I think I remember seeing Links and Rechts on the inside, German for left and right. But it's easy enough to figure out which side they go on. Take one of them and just slide it onto the head. If the lines on the cover essentially draw a connection between the intake port to the exhaust port, they are on the proper side. Otherwise, swap covers.
    Kurt -- Forum Liaison ---> 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!

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