oil leak, possible cracked block?

[ujmfan]

My 1979 GS 850 has a bad oil leak. It appears to be coming from the engine block right between the left 2 cylinders (below the valve gasket and above the head gasket). It is dripping at a rate of a drop every second. I was told it looks like a cracked block. I am also told this would be expensive to fix. I have a car mechanic that can help me with this, but he might not know much about bikes.

One thing that was mentioned as a possible band aid is to try JB Weld on it. What do you think?

If that doesn't work, would it be cheaper to try to find a used engine and just replace what I have? This engine has 35,000 miles on it and runs well except for the oil leak. If just replacing the engine would be a good option, can I put a GS 1000 engine in this bike? It is shaft drive.

[runewolf]

Man it is hard to crack these blocks... try to grab a picture of it so maybe we can see how bad you are talking.

[49er]

From your description, the oil is coming from the head area, probably the cam cover ( valve gasket area?). If you have recently bought this bike the previous owner may have adjusted the valve clearances and damaged the cover gasket.
Oil is supplied to the camshafts via the outer stud sleeves (#1 & 4 cylinders) and any leaks here through damaged head gaskets/o rings usually allows oil to be sprayed over the carbs and airbox. When the bike is stationary it runs down the cylinder fins.
The position of the leak would suggest that there is no crack in your cylinders. Good luck.

Ian

[Nobby 'C ']

Are you sure that it is not coming from the cam chain tensioner gasket? They are a known weak point.

[Plasterdog]

The "drop every second" is that while the motor is running?

Like Runewolf said these are hard to crack. Clean the area around the leak and start up, then watch to see where the drips starts forming.
Good luck.

[ujmfan]

49er,

I think you are right on the money. I had neglected to mention that I had just bought this bike in June and after a few hundred miles I had a fuse blow because oil had dripped down onto the fuse box. I had traced that oil drip to the air box. The air box had lots of oil in it. The valve gasket looks new, so I think that is the problem.
When I checked for the oil leak, obviously the bike was stationary. <img> The oil was dripping from the 5th fin down, between the two outside cylinders on the left side of the bike. Good call.

I hope you are right (and runewolf says these blocks are hard to crack). I am encouraged now to check with my mechanic friend to help me. We can deal with an upper gasket. Anything more than that would probably have to go to a shop.

I just joined this group today and I am already a huge fan! Thanks.

[ujmfan]

I will check on that. Thanks.

[t3rmin]

I'm not sure how the air box would get oil *IN* it unless it were coming through the breather tube...

[JayH]

I'm not sure how the air box would get oil *IN* it unless it were coming through the breather tube...

More than likely the foam air filter was over oiled when it was put back in the air cleaner.

[t3rmin]

More than likely the foam air filter was over oiled when it was put back in the air cleaner.

... or that. ;-)

[riskadh]

Actually, I had oil in my air filter, but that was because of my crank case filling up with gasoline from the petcock. Make sure you run it in 'ON' and that it is not defective. Fixed my petcock, changed the oil and it runs fine with no leaks whatsoever. At least, that was why oil was leaking out of my air filter.

[flyingace]

With oil leaking that fast, it should be easy to see where it's coming from. If not, just clean the engine with engine cleaner to rid it of old oil and dirt. Then you can isolate the source easier once the bike is running.

[ujmfan]

Good news - the leak is in the valve cover gasket

My mechanic and I worked on this last night and found the head is not cracked. I did not realize there is a vent (or weep hole) from the recessed areas on top of the head. The leak from the gasket was pooling in the recessed area and then dripping out the weep hole between the exhaust pipes. Sorry, I am not real mechanically inclined.

The gasket looked good, so we tried cleaning it up and the head and then reusing it. It did not work. We will replace the gasket Saturday.

I notice in previous postings there has been some discussion about whether to use a sealer (silicone) on the gasket or to put it on dry. Anyone have strong suggestions about this?

Also, what are the torque specs on a GS 850G? I checked previous posts on this and also noticed varying answers.

[49er]

ujmfan

Pleased to here that you have sorted your oil leak out.
The Clymer manual (GS 850-1100 Shaft Drive 1979-1984) quotes the torque figure of 6.5 foot pounds for the cover bolts. When I fit a new cover gasket I smear each side with vaseline (petrolium jelly). This prevents the gasket from sticking to the aluminium surfaces and allows it to be reused on future occasions. If you choose to use silcone on mating surfaces you need to ensure that no surplus silicone gets squeezed into any adjacent oil galleys or breather holes.