Torn push rod seal; Replace head gasket and o-rings??

Blane · 10-06-2012, 08:56 AM

I'm putting together an R100 Frankenbeemer. I just got the heads on and everything torqued up a couple of weeks ago and noticed when I was installing the exhaust today that one of the new push rod seals was torn.

Now everything on the right side has to come off to replace that stinkin' seal. My question is, even though the bike hasn't been running, am I going to have to replace the head gasket again? Also this is one of those cylinders that requires a large o-ring around the cylinder and the 2 o-rings around the studs. Am I going to have to replace those as well? I just want to make sure I order everything at once and save on shipping.

bay · 10-06-2012, 09:02 AM

hi,you will only have to replace the two small o rings and the larger base o ring ,i would of thought the head gasket is fine.i have had the heads off mine and reused the gasket with no ill effects.

mykill · 10-06-2012, 09:16 AM

Leave the head attached to the barrel with the 12 and 6 o'clock bolts. No need to replace the o-rings, they are still fresh.
Just slide the barrel out with engine at TDC keeping the rings in place. If you used sealant at the base, you have some cleaning to do and careful but awkward re-application. But no big deal.

disston · 10-06-2012, 09:44 AM

A lot of riders would take the wrist pins out of the pistons so the pistons will stay in the cylinders and the heads stay on top of the cylinders. It's OK to do that way but be very careful when reinstalling the wrist pin circlips. The circlips have to be prooved or proofed. There's not a lot you can see when performing this operation and everything is still attached to the engine. There is just not a lot of room to stick your head in there.

Even a circlip installed in a place where you can see what is happening is proofed. Once installed, you think it's in place, the circlip is spun in it's bore. Spin it enough so that you can see it is seated. That's it. Prove all circlips.

My friend lost a piston, cylinder, cam shaft, oil pump and lifters. Because a circlip was not fully seated.

Uncle Pollo · 10-06-2012, 10:06 AM

Take the valve ro kers off and move the whoe thin up a bit. Tdc or u will spend some time with the ri.g compressor. Master te h at bmw did all pushrod seals that way. 30 minutes. Readjust the valves before reinstaling valve covers.

supershaft · 10-06-2012, 12:53 PM

Where did you get the seals Blaine?

Padmei · 10-06-2012, 01:38 PM

Have you checked for leaks? I put one in a few weeks ago that got a bit squished & a bit is hanging out. I didn't notice it till after I'd ridden it for a few hundred Kms.
Replace if you want- it may bug you that it is there smirking at you

- but it may not leak at all.

I got mine from motobins.

Box'a'bits · 10-06-2012, 01:48 PM

Quote:

Originally Posted by Padmei

I put one in a few weeks ago that got a bit squished & a bit is hanging out. I didn't notice it till after I'd ridden it for a few hundred Kms. Replace if you want- it may bug you that it is there smirking at you

- but it may not leak at all.

Padmei · 10-06-2012, 01:49 PM

barstard

Blane · 10-06-2012, 02:29 PM

Quote:

Originally Posted by supershaft

Where did you get the seals Blaine?

From Hans at Hucky's BMW Parts.

Wirespokes · 10-06-2012, 03:26 PM

I wouldn't replace the ORings. As said, they're still fresh.

I've re-used used head gaskets in my bikes many times, only freshening the sealant around the top studs and pushrod tubes. Hasn't been a problem yet. And in your case, it's still new with no heat cycles - but best to leave the head and cylinder together.

supershaft · 10-06-2012, 05:42 PM

Quote:

Originally Posted by Blane

From Hans at Hucky's BMW Parts.

I wonder if they are BMW. There are some bad ones floating around from Motobins or Capital Cycle or some place like that.

Or maybe it was from BMW (the bad ones). They are selling crap as if they were Capital cycle lately. I just got a new cadnium plated front axle. WTF? It's going to turn to rust in no time.

Prutser · 10-06-2012, 06:05 PM

Did you put any sealant on the push rod tubes before the seals where put on them ?

Have seen a lot of those seals slide over the ring on the tube and than burst because some sealant was used there.

Just thinking why they would burst.
Of course there could be some bad ones out there.

Blane · 10-07-2012, 04:05 AM

Quote:

Originally Posted by Padmei

Have you checked for leaks? I put one in a few weeks ago that got a bit squished & a bit is hanging out. I didn't notice it till after I'd ridden it for a few hundred Kms.
Replace if you want- it may bug you that it is there smirking at you

- but it may not leak at all.

I got mine from motobins.

The tear looks pretty deep from where I could see. You might be right about holding a seal but it won't take long to replace them.

Blane · 10-07-2012, 04:08 AM

Quote:

Originally Posted by Prutser

Did you put any sealant on the push rod tubes before the seals where put on them ?

Have seen a lot of those seals slide over the ring on the tube and than burst because some sealant was used there.

Just thinking why they would burst.
Of course there could be some bad ones out there.

No sealant. Just regular motor oil inside and out as Oak recommends.

10-06-2012, 08:56 AM	#1
Blane ^OP Gnarly Adventurer Joined: Apr 2006 Location: East of Slowdessa Oddometer: 281	Torn push rod seal; Replace head gasket and o-rings?? I'm putting together an R100 Frankenbeemer. I just got the heads on and everything torqued up a couple of weeks ago and noticed when I was installing the exhaust today that one of the new push rod seals was torn. Now everything on the right side has to come off to replace that stinkin' seal. My question is, even though the bike hasn't been running, am I going to have to replace the head gasket again? Also this is one of those cylinders that requires a large o-ring around the cylinder and the 2 o-rings around the studs. Am I going to have to replace those as well? I just want to make sure I order everything at once and save on shipping. __________________ --------<>-------- 2004 R1150GS Adventure (The Valdez) 1973 R75/5 Red Toaster (Amy)

10-06-2012, 09:02 AM	#2
bay Adventurer Joined: Aug 2010 Location: south demark Oddometer: 30	torn pushrod seal hi,you will only have to replace the two small o rings and the larger base o ring ,i would of thought the head gasket is fine.i have had the heads off mine and reused the gasket with no ill effects.

10-06-2012, 09:16 AM	#3
mykill odd Joined: Feb 2008 Location: Los Angeles Oddometer: 1,092	Leave the head attached to the barrel with the 12 and 6 o'clock bolts. No need to replace the o-rings, they are still fresh. Just slide the barrel out with engine at TDC keeping the rings in place. If you used sealant at the base, you have some cleaning to do and careful but awkward re-application. But no big deal. __________________ Never underestimate the laxative properties of motorcycling.

10-06-2012, 09:44 AM	#4
disston ShadeTreeExpert Joined: Mar 2011 Location: Silver Spring, Md Oddometer: 4,980	A lot of riders would take the wrist pins out of the pistons so the pistons will stay in the cylinders and the heads stay on top of the cylinders. It's OK to do that way but be very careful when reinstalling the wrist pin circlips. The circlips have to be prooved or proofed. There's not a lot you can see when performing this operation and everything is still attached to the engine. There is just not a lot of room to stick your head in there. Even a circlip installed in a place where you can see what is happening is proofed. Once installed, you think it's in place, the circlip is spun in it's bore. Spin it enough so that you can see it is seated. That's it. Prove all circlips. My friend lost a piston, cylinder, cam shaft, oil pump and lifters. Because a circlip was not fully seated. __________________ Never memorize something you can look up. ---Albert Einstein

10-06-2012, 10:06 AM	#5
Uncle Pollo Von Hochstaden's son Joined: Jun 2006 Location: Albuquerque, Neue Messico Oddometer: 44,956	Take the valve ro kers off and move the whoe thin up a bit. Tdc or u will spend some time with the ri.g compressor. Master te h at bmw did all pushrod seals that way. 30 minutes. Readjust the valves before reinstaling valve covers. __________________ mikuni vm32-33 both sides :\ 5000 feet altitude/ 140 main \ 159 02 needle jet\ 6F4 needle in the middle setting\ 0.5 air jet\ pilot 25/3.0 slide 35 mpg around town riding like a asno

10-06-2012, 12:53 PM	#6
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,041	Where did you get the seals Blaine?

10-06-2012, 01:38 PM	#7
Padmei enamoured Joined: Mar 2008 Location: Nelson New Zealand Oddometer: 2,477	Have you checked for leaks? I put one in a few weeks ago that got a bit squished & a bit is hanging out. I didn't notice it till after I'd ridden it for a few hundred Kms. Replace if you want- it may bug you that it is there smirking at you - but it may not leak at all. I got mine from motobins.

10-06-2012, 01:49 PM	#9
Padmei enamoured Joined: Mar 2008 Location: Nelson New Zealand Oddometer: 2,477	barstard

10-06-2012, 03:26 PM	#11
Wirespokes Beemerholics Anonymous Joined: Jul 2002 Location: Jackson's Bottom Oregon Oddometer: 7,354	I wouldn't replace the ORings. As said, they're still fresh. I've re-used used head gaskets in my bikes many times, only freshening the sealant around the top studs and pushrod tubes. Hasn't been a problem yet. And in your case, it's still new with no heat cycles - but best to leave the head and cylinder together. __________________ Wanted: Dead, smashed, crashed or trashed gauges BMW GAUGE REPAIRS - TACHSPEEDOCLOCKVOLT METER PODs & LIGHT BOARD*

10-06-2012, 06:05 PM	#13
Prutser Studly Adventurer Joined: Aug 2012 Location: The Dutch swamp Oddometer: 505	Did you put any sealant on the push rod tubes before the seals where put on them ? Have seen a lot of those seals slide over the ring on the tube and than burst because some sealant was used there. Just thinking why they would burst. Of course there could be some bad ones out there. __________________ BMW R100'91/R80'93/R80ST'83/R65GS'87/GasGasTXT300/DouglasW20-1920 R100GS'91 (sold)

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