Airhead pushrod seals

[TEXASYETI]

Anyone ever replace these on their airhead? I've got all the tools and the parts but am looking for any tips / hints / suggestions about this repair?

[Rubber Cow]

I've done this a few times.
You'll need:
-New valve cover seals and cylinder O-rings.
-New tube of Dirko or Yamabond
-New o-ring seals, 2 per side on the top-most engine stud oil gallies.


The big thing to remember is to TAKE YOUR TIME!

Remove the valve assemblies by bringing to torque down sequentially and slowly. Keep the towers assembled but remeber to inspect the rocker arm shaft wear surfaces and the rocker arm needle bearings.
Remember to locate the dot on the rocker arm shafts in the correct orientation for oil flow when you reassemble them.

You can disconnect the wrist pin and leave the piston in the cylinder. This wil save you a lot of grief and time.

Clean all of the seal mating surfaces with a good solvent and try not to get any crap in motor. Get rid of any traces of oil in the motor recesses for the pushrod tube seal with a good solvent and a clean rag.

I like to smear a little Dirko or Yamabond onto the face of the pushrod seal where it meets the motor. Most mechanics I know don't think that it does any harm.

Check you valve rocker end float (vertical movement) before you go to the trouble of adjusting valves. Shim if necessary. Buy a few different-sized shims beforehand and keep them around.

Hope this helps.
Let us know if you get stuck or need any more tips/help.
Cheers,
Jorge

[wirewrkr]

Originally Posted by Rubber Cow

I've done this a few times.
You'll need:
-New valve cover seals and cylinder O-rings.
-New tube of Dirko or Yamabond
-New o-ring seals, 2 per side on the top-most engine stud oil gallies.


The big thing to remember is to TAKE YOUR TIME!

Remove the valve assemblies by bringing to torque down sequentially and slowly. Keep the towers assembled but remeber to inspect the rocker arm shaft wear surfaces and the rocker arm needle bearings.
Remember to locate the dot on the rocker arm shafts in the correct orientation for oil flow when you reassemble them.

You can disconnect the wrist pin and leave the piston in the cylinder. This wil save you a lot of grief and time.

Clean all of the seal mating surfaces with a good solvent and try not to get any crap in motor. Get rid of any traces of oil in the motor recesses for the pushrod tube seal with a good solvent and a clean rag.

I like to smear a little Dirko or Yamabond onto the face of the pushrod seal where it meets the motor. Most mechanics I know don't think that it does any harm.

Check you valve rocker end float (vertical movement) before you go to the trouble of adjusting valves. Shim if necessary. Buy a few different-sized shims beforehand and keep them around.

Hope this helps.
Let us know if you get stuck or need any more tips/help.
Cheers,
Jorge

Okay Jorge, Just how do you know what year and model bike he has to give him this information?
Not all bikes use the orings on the studs, not all bikes have end pay shims and if it's a typical /5 he will drive himself nuts trying to get the end-play out of the rockers EVEN if he replaces the original wavy sims with the later non wavy ones. SO MANY different ways to do this job, SO MANY different bikes, although I agree that you can do the job without pulling the piston out of the jug, ( I do it that way cuz I'm lazy) I DON"T agree with you on sealing the PR seals with goop. Never done it never will.
Robert

[Kentucky]

An old airhead guru taught me this trick and it has worked twice for me. If your pushrod seals have an alloy ring around the outside you can take a block of wood and tap them in all the way around using a mallet. Just work them in with a decent lick all the way around striking the alloy ring in about four or five places. It drives the seals back in. Both times it worked like a champ for me.

Barry

[wintonio]

Originally Posted by wirewrkr

Okay Jorge, Just how do you know what year and model bike he has to give him this information?
Not all bikes use the orings on the studs, not all bikes have end pay shims and if it's a typical /5 he will drive himself nuts trying to get the end-play out of the rockers EVEN if he replaces the original wavy sims with the later non wavy ones. SO MANY different ways to do this job, SO MANY different bikes, although I agree that you can do the job without pulling the piston out of the jug, ( I do it that way cuz I'm lazy) I DON"T agree with you on sealing the PR seals with goop. Never done it never will.
Robert

Robert-

Not to be a dick, but are you seriously going to drag out a thread that has been dead for 4 and a half years and critique the advice?

unless that dude is even lazier than I am, he has long since changed out the damn pushrod seals.

edit: fill out your profile, let us know who you are

[Rubber Cow]

Originally Posted by wirewrkr

Okay Jorge, Just how do you know what year and model bike he has to give him this information?
Not all bikes use the orings on the studs, not all bikes have end pay shims and if it's a typical /5 he will drive himself nuts trying to get the end-play out of the rockers EVEN if he replaces the original wavy sims with the later non wavy ones. SO MANY different ways to do this job, SO MANY different bikes, although I agree that you can do the job without pulling the piston out of the jug, ( I do it that way cuz I'm lazy) I DON"T agree with you on sealing the PR seals with goop. Never done it never will.
Robert

Gee....I guess I just looked at his public profile and noticed that he was on a '92GS or '93 GSPD....the same bike(s) I'd done this work on. Including sealing the seals. The one that's still around is still not leaking 8+ years later.
Yeah it's an old thread.
If you've got something constuctive to add then add it. If not, STFU.
Or should I translate that for you?
Cheers,
Jorge

[opposedcyljunkie]

Originally Posted by wintonio

Not to be a dick, but are you seriously going to drag out a thread that has been dead for 4 and a half years and critique the advice?

+1

maybe the bike in question is already long gone...

[mark1305]

Originally Posted by Kentucky

An old airhead guru taught me this trick and it has worked twice for me. If your pushrod seals have an alloy ring around the outside you can take a block of wood and tap them in all the way around using a mallet. Just work them in with a decent lick all the way around striking the alloy ring in about four or five places. It drives the seals back in. Both times it worked like a champ for me.

Barry

Kentucky, are you talking about this method to tap the seals back in without pulling everything down for replacement? Or just as a method for seating new seals?

Mine are weeping on one side, but nothing wiping with a rag once or twice a week won't fix, so I'm not in a hurry to go into the motor yet. But if that works in situ, I'll probably give it a shot.

[Rubber Cow]

Originally Posted by Kentucky

An old airhead guru taught me this trick and it has worked twice for me. If your pushrod seals have an alloy ring around the outside you can take a block of wood and tap them in all the way around using a mallet. Just work them in with a decent lick all the way around striking the alloy ring in about four or five places. It drives the seals back in. Both times it worked like a champ for me.

Barry

Is that on your '72 or '94?
I believe the post '78 twins have a brazed collar that can't be tapped in as you described.
Cheers,
Jorge

[TEXASYETI]

That was my old ADVRider screen name and it's nice to see old threads never die.

FWIW, I did replace the seals and Jorge, your input was very valuable.

Since that initial effort I have worked with a few BMW wrenches who used a little silicon sealant on the surface where the seal meets the block. Not a lot, just a skim coat. Works like a charm.

[Kentucky]

Originally Posted by mark1305

Kentucky, are you talking about this method to tap the seals back in without pulling everything down for replacement? Or just as a method for seating new seals?

Mine are weeping on one side, but nothing wiping with a rag once or twice a week won't fix, so I'm not in a hurry to go into the motor yet. But if that works in situ, I'll probably give it a shot.

Yes that is what I am saying. You simply leave everything in place and tap them in further. I'm not sure what percentage of time this works. I do know that it has worked for me twice. Once on one of my current airheads and once on another. I cannot see a downside to this technique. It either works for you or it doesn't. Someone else here may know a reason not to do it however. I simply took a nice 1x1 wood stick and a mallet to it with about four sharp hits around the seal.

Barry

[mark1305]

Sounds worth a closer look. My seals appear to have a metal ring that fits close around, but not attached to the pushrod tubes. As soon as it cools down on the driveway this evening, I plan to give it a try.

Worst that can happen is that I'll increase the weepage and have to change the seals - and that may be getting closer anyway. I noticed on the right side, which doesn't leak a bit, the seals are getting dry cracks in the rubber. So I know the day is coming.

[Kentucky]

Originally Posted by Rubber Cow

Is that on your '72 or '94?
I believe the post '78 twins have a brazed collar that can't be tapped in as you described.
Cheers,
Jorge

I did that on my 72 and an R90/6.
Barry

[Boon Booni]

Originally Posted by Kentucky

I did that on my 72 and an R90/6.
Barry

Wow, a '72 huh? And here I though they didn't start the /6 series until '74..


Why the big fuss about leaving the piston in the cylinder? It takes a little finger pressure and all of about 10-15 seconds to get the pistons back in the cylinders.. At least on my '74 R90/6..

Duane does them pretty quick too... BMW Piston Ring Compressor..

[wirewrkr]

Originally Posted by Rubber Cow

Gee....I guess I just looked at his public profile and noticed that he was on a '92GS or '93 GSPD....the same bike(s) I'd done this work on. Including sealing the seals. The one that's still around is still not leaking 8+ years later.
Yeah it's an old thread.
If you've got something constuctive to add then add it. If not, STFU.
Or should I translate that for you?
Cheers,
Jorge

Well so what?
A little hostile are we? Dude, grow up.
Robert