Rear main leak...or ??? - Page 2

supershaft · 01-06-2013, 08:39 PM

That oil could not only be from the tranny input seal but it could also be from the clutch rod. You need to look at ALL the possibilities. It might be from the RMS too. I can't tell from those pictures. If that isn't the original seal it is the original type. The later types are SO much better. I would replace it. I would be tempted to replace that original oil pump cover for the same reasons. Plus it very well could be a big source of the oil.

ME 109 · 01-06-2013, 09:24 PM

My later type oil pump cover sent me on a freakin' wild goose chase when it developed a hairline crack in the top left counter-bored hole.
It presented symptoms of a leaking rms or worn guide ring or guide ring o-ring.

I was advised (by GSPD) to run the motor without the tranny and clutch installed. Bingo! the leak identified itself almost immediately.

The earlier angled counter-sunk type covers could not present this issue imo.

I am proud to be the recipient of never before heard of airhead problems. True pioneering

Beemerguru · 01-06-2013, 09:59 PM

Make sure you chase out the bolt holes for the oil pump cover. Previous owners/mechanics may have used Locktite to hold the bolts. Since the torque is only about 7lbs, any interference means the cover isn't seated..and will leak...again.

Actually, I think you should use some blue so the bolts stay in place.

supershaft · 01-06-2013, 10:11 PM

I always heat them up in case some numnut has put red loctite on them. I always chase those threads. Not with a cutting tap but with a thread cleaner or a roll tap.

ME 109 · 01-06-2013, 10:22 PM

Quote:

Originally Posted by supershaft

I always heat them up in case some numnut has put red loctite on them.

Ah, the joys of having the same motorcycle for coming up twenty years.
I know exactly what the numbnut has done.

Kai Ju · 01-06-2013, 11:40 PM

Quote:

Originally Posted by ME 109

The earlier angled counter-sunk type covers could not present this issue imo.

Not so sure about that. I would think that an over torqued countersunk screw could cause a crack easier than a flat bolt head.
I realize that I'm comparing apples to oranges ( plastic vs. steel ) but I saw so many leaking neutral switch plates on RDs due to cracks from over torqued C/S screws. The key was loctite and just snug the screw enough to seat the cover and compress the O-ring. Let the loctite take care of the bolt retention.

ME 109 · 01-07-2013, 01:06 AM

Quote:

Originally Posted by Kai Ju

Not so sure about that. I would think that an over torqued countersunk screw could cause a crack easier than a flat bolt head.
I realize that I'm comparing apples to oranges ( plastic vs. steel ) but I saw so many leaking neutral switch plates on RDs due to cracks from over torqued C/S screws. The key was loctite and just snug the screw enough to seat the cover and compress the O-ring. Let the loctite take care of the bolt retention.

The counterbore for the bolt head is what caused the problem. The bottom of the counterbore is ever so close to the o-ring groove on the other side. Perhaps my cover was somehow over machined bringing it too close to the o-ring groove.
Mind you, this cover was at least 25 years old and had only been taken off once. Possibly over torqued.

hardwaregrrl · 01-07-2013, 05:25 AM

Woodly, don't know how far you are into the disassembly so apologies if this is 205. Please disconnect the neg cable on the battery BEFORE you remove the front cover. You could damage your diode board.

JonnyCash · 01-07-2013, 05:28 AM

Quote:

Originally Posted by Kai Ju

Not so sure about that. I would think that an over torqued countersunk screw could cause a crack easier than a flat bolt head.
I realize that I'm comparing apples to oranges ( plastic vs. steel ) but I saw so many leaking neutral switch plates on RDs due to cracks from over torqued C/S screws. The key was loctite and just snug the screw enough to seat the cover and compress the O-ring. Let the loctite take care of the bolt retention.

Yeah, but on an RD the switch is made of plastic!

Oops. Sorry for the drive-by posting there. I see you acknowledged the fact that it's plastic.

woodly1069 · 01-07-2013, 05:45 AM

Quote:

hardwaregrrl • Today 08:25 AM
Woodly, don't know how far you are into the disassembly so apologies if this is 205. Please disconnect the neg cable on the battery BEFORE you remove the front cover. You could damage your diode board.

The bike is totally disassembled at this point so the battery is long gone! Thanks for the heads up! I do have one question though, what is referred to as the RMS the rear main seal?

pommie john · 01-07-2013, 05:48 AM

Quote:

Originally Posted by woodly1069

The bike is totally disassembled at this point so the battery is long gone! Thanks for the heads up! I do have one question though, what is referred to as the RMS the rear main seal?

Yep RMS = Rear Main Seal

pommie john · 01-07-2013, 05:51 AM

One thing. have you tried smelling the oil residue ? Transmission oil smells completely different from engine oil. That could give you a clue where it's coming from.

backdrifter · 01-07-2013, 06:17 AM

Not to beat a dead horse - but please be sure to check if the crank has moved forward as jackd prescribed. If it has not, block it immediately. If it HAS, I've read of a few last ditch tricks that may help you re-seat the thrust bearings. If that fails, unfortunately, it's time for total engine disassembly.

I got lucky in that I read about blocking the crank just before I got that deep into my engine.

For the record, both my rear main seal and oil pump cover were leaking, but then again, so was every gasket and o-ring on the entire bike!

supershaft · 01-07-2013, 01:38 PM

Quote:

Originally Posted by ME 109

Ah, the joys of having the same motorcycle for coming up twenty years.
I know exactly what the numbnut has done.

I work on them for a living.

ignatz72 · 01-07-2013, 01:45 PM

Quote:

Originally Posted by supershaft

I work on them for a living.

SS, Me109 was referring to himself - he is his own numbnuts PO.

01-06-2013, 09:24 PM	#17
ME 109 Studly Adventurer Joined: Jun 2009 Location: Albury Australia Oddometer: 583	My later type oil pump cover sent me on a freakin' wild goose chase when it developed a hairline crack in the top left counter-bored hole. It presented symptoms of a leaking rms or worn guide ring or guide ring o-ring. I was advised (by GSPD) to run the motor without the tranny and clutch installed. Bingo! the leak identified itself almost immediately. The earlier angled counter-sunk type covers could not present this issue imo. I am proud to be the recipient of never before heard of airhead problems. True pioneering __________________ Lord of the Bings

01-06-2013, 09:59 PM	#18
Beemerguru Beemerguru...G/S guy Joined: Nov 2006 Location: Foster City, CA Oddometer: 635	Make sure you chase out the bolt holes for the oil pump cover. Previous owners/mechanics may have used Locktite to hold the bolts. Since the torque is only about 7lbs, any interference means the cover isn't seated..and will leak...again. Actually, I think you should use some blue so the bolts stay in place. __________________ Greg Hutchinson BMW Club of Northern California, Ambassador, BMW MOA, Vice President Vintage BMW Club http://gregsgssite.shutterfly.com/

01-07-2013, 05:25 AM	#23
hardwaregrrl Shit for brains Joined: Jan 2006 Location: Atlanta Oddometer: 4,851	Woodly, don't know how far you are into the disassembly so apologies if this is 205. Please disconnect the neg cable on the battery BEFORE you remove the front cover. You could damage your diode board. __________________ Trans Lab RR-broke down in Ontario-2 stroke fun for 200 bucks- TCAT R100 GS racks For Sale My life aboard an R80ST

01-07-2013, 05:51 AM	#27
pommie john Beastly Adventurer Joined: Apr 2008 Location: Brisvegas, Australia Oddometer: 1,109	One thing. have you tried smelling the oil residue ? Transmission oil smells completely different from engine oil. That could give you a clue where it's coming from. __________________ The trouble with the world is that the stupid are cocksure and the intelligent are full of doubt. Bertrand Russell

01-07-2013, 06:17 AM	#28
backdrifter Wannabe rider Joined: Jan 2005 Location: Belleville, IL Oddometer: 1,308	Not to beat a dead horse - but please be sure to check if the crank has moved forward as jackd prescribed. If it has not, block it immediately. If it HAS, I've read of a few last ditch tricks that may help you re-seat the thrust bearings. If that fails, unfortunately, it's time for total engine disassembly. I got lucky in that I read about blocking the crank just before I got that deep into my engine. For the record, both my rear main seal and oil pump cover were leaking, but then again, so was every gasket and o-ring on the entire bike! __________________ "We are very good at preparing to live, but not very good at living." -Thich Nhat Hanh 1973 BMW R60/5

01-06-2013, 08:39 PM	#16
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,046	That oil could not only be from the tranny input seal but it could also be from the clutch rod. You need to look at ALL the possibilities. It might be from the RMS too. I can't tell from those pictures. If that isn't the original seal it is the original type. The later types are SO much better. I would replace it. I would be tempted to replace that original oil pump cover for the same reasons. Plus it very well could be a big source of the oil.

01-06-2013, 10:11 PM	#19
supershaft because I can Joined: Sep 2010 Location: San Francisco Bay area Oddometer: 6,046	I always heat them up in case some numnut has put red loctite on them. I always chase those threads. Not with a cutting tap but with a thread cleaner or a roll tap.

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