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Thread: 1978 R80 pushrod tube seals

  1. #1
    Nick Kennedy
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    1978 R80 pushrod tube seals

    Hi All
    Can any one help me out with a parts list I need to replace the pushrod seals please.
    I obviously need the 4 pushrod seals, what else? Is there a gasket under the cylinder that needs replacing?
    What else? I will leave the head attached to the cylinder.
    Also can any one give me a link to those repair videos, I think the guys name is Chris ? The guys that drops alot of f bombs ya know!
    Thanks in advance
    Nick Kennedy

  2. #2
    Registered User m_stock10506's Avatar
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    Quote Originally Posted by nickrides View Post
    Hi All
    .................. replace the pushrod seals please.
    .................
    Also can any one give me a link to those repair videos, I think the guys name is Chris ? The guys that drops alot of f bombs ya know!
    Thanks in advance
    Airhead Pushrod Tube Seals R&R (Chris Harris) 3 Parts
    https://www.youtube.com/watch?v=A47LiKSYD9o
    https://www.youtube.com/watch?v=yEFTNrxsWI8
    https://www.youtube.com/watch?v=Y9R_i-w71Rg
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  3. #3
    Registered User m_stock10506's Avatar
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    Here's another.

    Pushrod seals - Illinois BMW Riders (44 minutes)
    https://www.youtube.com/watch?v=ib_VblhJ6Q0
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  4. #4
    Liaison 20774's Avatar
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    Nick -

    Check my signature line link for a section on this...other websites out there. I personally like Oak Okleshen's top end manual...pretty cheap and still available from his estate. His email address is in my signature line link.

    Are you going to pull the head-cylinder combo off the studs? Note there are two small O-rings that are on the upper studs and really should be replaced. You will need to scrupulously clean the engine base and cylinder base and use a sealant. Mind the upper two studs have an oil path from inside the crankcase to the upper studs...this is how oil gets to the rocker arms. You don't want to plug those holes.
    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!

  5. #5
    Nick Kennedy
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    Hey Boys Thanks for the advice and video links, I'm going for it!
    The dripping has reached it limit for me to tolerate.
    I'll let you know how it turns out, I'm sure it will be fine,
    I love that R80, she is a sweet bike to ride!
    Right now she has Avon Roadrider tires on, those are great BTW! Easy to take on or off by the side of the road, I know I've done it. Those Michelins are great tires, but I don't think I could take them off to fix a flat on the side of the road, just saying.

  6. #6
    I would replace all these parts:

    base gaskets
    rocker cover gaskets
    O-rings
    push rod seals (and I would also use a little hi-temp silicon sealer on these - just a light film)
    I also liked the factory BMW gasket sealer for the base gaskets/Orings. I purchased a tube from Max's BMW. A tube would last a lifetime.

    Also, while in there, decarb the top of the pistons and the insides of the heads. When pulling out the cylinders, make sure that the piston/rings assys. do not fall down onto the bottom studs. I used some rubber tubing on the studs (sliced end to end so that they could be pulled off while getting the cylinders started back on and back over the pistons) to make sure that the pistons are protected, or a soft piece of wood across the studs to hold pistons up while cleaning/servicing the other stuff.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  7. #7
    Liaison 20774's Avatar
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    It's important also to not let the conrod fall and hit the engine case opening.
    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!

  8. #8
    Day Dreaming ... happy wanderer's Avatar
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    Quote Originally Posted by SCBuckeye View Post
    I would replace all these parts:

    base gaskets
    rocker cover gaskets
    O-rings
    push rod seals (and I would also use a little hi-temp silicon sealer on these - just a light film)
    I also liked the factory BMW gasket sealer for the base gaskets/Orings. I purchased a tube from Max's BMW. A tube would last a lifetime.

    Also, while in there, decarb the top of the pistons and the insides of the heads. When pulling out the cylinders, make sure that the piston/rings assys. do not fall down onto the bottom studs. I used some rubber tubing on the studs (sliced end to end so that they could be pulled off while getting the cylinders started back on and back over the pistons) to make sure that the pistons are protected, or a soft piece of wood across the studs to hold pistons up while cleaning/servicing the other stuff.
    This sounded wrong to me so I checked Oak's Top End Manual. He (and Tom Cutter and Snowbum) do not recommend using sealant of any kind on the large base O Rings or the push tube seals. These are prepared with clean engine oil and only at the time of install. The oil causes these rubber parts to expand as they should. Once the O Rings are lightly covered in oil you need to assemble things pretty quick or assembly becomes difficult due to swelling.

    For the base of the cylnders a very light film of Hylomar or Permatex Ultra Gray or Pro-Seal Red Silicone 700 deg F or... some high temp, flexible, easy to remove sealant intended for this purpose. I've used Permatex Ultra Gray twice now with no leaks. Be very careful around the top stup crankcase openings. Too much sealant can block oil flow through here which is critical to top end lubrication.
    MJM - BeeCeeBeemers Motorcycle Club Vancouver B.C.
    '81 R80G/S, '82 R100RS, '00 R1100RT

  9. #9
    I just did this on my 75/5, it doesn't have the O-rings, but otherwise similar. I separated head and cylinder though and also removed the piston since I did have to re-thread a stud.

    On the base I used a new gasket with a tiny amount of the grey sealant (Honda product). Careful not to obstruct the oil bores.
    New gasket on the head, no sealent
    New valve cover gasket.

    All tight and no issues, don't forget to re-torque the heads and adjust valves after a while as recommended by the pros. Mine really needed it!
    Olaf - Austin, TX MOA #200565
    Current bikes: 2012 R1200R Classic, 1973 R75/5 www.R75slash5.com, 1969 CT 70 (108 cc engine)

  10. #10
    The OP indicated that he intends to leave the head attached to the cylinder when renewing the pushrod seals. This means that the 12 and 6 o'clock nuts will remain on the studs. Personally, I would slightly loosen these nuts (about 1/4 turn) just to relieve some of the tension on the studs, but not enough to disturb the head gasket. The head gasket is usually the most expensive component in pushrod seal renewal if the head is removed. If the head is not removed, barring other issues, the process can be done in a few hours fairly inexpensively.

    An exception is having to replace the exhaust nut. This is illustrated in the video from the Illinois BMW club. A stuck exhaust nut can be removed without incurring more damage to the threads on the head.

    Not fully illustrated in the Illinois video is the removal and replacement of the clip securing the wrist pin in the piston. The fellow doing the video had to put the camera down to remove the clip and re-insertion was done in a manner that was not captured by the camera.

    I found it somewhat difficult to remove and replace the clip the first time I undertook this operation. Somewhere in the house that I use to live in, in several dark recesses of the garage, are a couple of these little clips. I am glad that they didn't fly into the engine case. Subsequent removal and insertion efforts went much easier. It is a very good idea to block the opening to the engine case with cardboard, rags, or something to lessen the likelihood of the clip entering the engine case. I would obtain several extra clips and I do not re-use old clips. My removal and insertion technique involves use of a very small "minus" screwdriver rather than needle nose pliers (as sort of shown in the Illinois video. )

    I use a reliable torque wrench and only torque the head bolts to 25 ft-lbs. I do the tightening in a cris-cross fashion (as shown in the factory and most other manuals). I apply torque in 3 stages, usually to 10 ft-lbs, then 18 ft-lbs, then 25 ft-lbs. The 12 and 6 o'clock nuts do not require nearly as much rotation as the other four nuts. When going to the 10 ft-lb torque I use a large C-clamp and a couple of appropriate sized sockets to slightly compress the rocker. I do this by feel. I do not want rotational movement about the rocker axis to be constrained, but I want minimal lateral movement.

    I have taken to using Yamabond (aka Hondabond) sealer at the base of the cylinder. I apply a very light coat to both the base of the cylinder and the engine case; typically I use a gloved finger. Care should be taken to not block the area about the top studs by using excess sealer.

  11. #11
    Liaison 20774's Avatar
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    RE: wrist pin circlips. Just want kind of circlips are expected on this '78 R80? On my '78 R100/7, the clips were external c-clips, easily removed with the appropriate circlip pliers. So, I suspect the same with the R80.

    However, upon installation of the Siebenrock kit to replace the worn out top end on my /7, the circlips were small sections of wire in the shape of the letter "C". These had to be pushed into the wrist pin hole until they popped into the keeper slot in the piston. That was relatively hard, and I'm not sure my thumbs have recovered! In the case of the my R69S, I had to remove and reinstall the "C" clips which ended up being doubly hard.

    But for the '78, I wouldn't expect that much trouble.
    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!

  12. #12
    On my 77 R100RS, 75 R60/6 and 71 R75/5 the wrist pins were all secured with the round wire in the groove outside the wrist pin. The first time was difficult; the fourth time was not difficult.

    On my 93 R100GS/PD the wrist pin was secured by the traditional circlip that is easily removed with a pair of circlip pliers.

    I have no idea about a 78 R80.

  13. #13
    Registered User lkchris's Avatar
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    Quote Originally Posted by SCBuckeye View Post
    I would replace all these parts:

    base gaskets
    rocker cover gaskets
    O-rings
    push rod seals
    O ring on base of cylinder as well as o rings on the cylinder mount studs

    Airhead rocker cover gaskets are good for ~10 years, so this may not be necessary.
    Kent Christensen
    21482
    '12 R1200RT, '02 R1100S, '84 R80G/S

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