My gas tank appears to be leaking engine oil

[Noreg]

Oh I made sure to torque valve cover bolts to spec with an inch-lb. wrench. A little less the second time. A little less still the third time. Don’t recall where I ended up the 4th time, but I know I wrote it in my service manual.

I have enough gasket material for 4 times, but I hope I won't need that much. But then again I am not at all mechanically inclined. I am really wanting to try the big city commuting on a bike. Filtering and all that.

Do I have to buy a valve kit? With the luck Im having I probably won't fit a single shim...

Wish I could just glue it shut and call it a day. It seems like a way faster leak than the last one.

I can't find the rings in the part fiche, not sure where they would belong.

[Rich82GS750TZ]

Don’t worry about the rings, I shouldn’t have even mentioned it. It’s really only usually considered if you either know that you have stuck rings, or you have the cylinders off anyway, and find that your piston rings are out of spec. I don’t think that’s very common and ring replacement usually happens with high miles.

Concentrating on the valve clearance check, follow your Factory service manual, get the spreadsheet from Steve, and get to work. He, and many others have written many posts on the forum regarding valve clearance and shim replacement. I can’t help, I have only done it on a 16 valve engine. It’s completely different, no shims. You have to be prepared to find valve clearances that are tighter then spec, requiring thinner shims. Proper sized shims will need to be sourced from somewhere. Sometimes shims can be swapped from one bucket to another to get the required clearance. That clearance and the whole process is detailed in the Factory Service Manual, Clymers, Haynes. I remember reading here that one or another of those may have provided somewhat confusing instructions on what direction the cam lobe should be in relative to the shim/bucket when measuring clearance. Again, not my forté, so I can’t help with the specifics. But you won’t know if your clearances are in spec til you get the cover off and measure them. Now, knowing that once you start the valve clearance checking process, you my very well have to wait for shims to finish it, you’ve got to ask yourself If you really want to start it before the trip. Obviously, your bike won’t make it with the valve cover gasket that’s in there. So, do you just hurry up and replace the gasket and ignore the valve clearance? I wouldn’t.

[Noreg]

Don’t worry about the rings, I shouldn’t have even mentioned it. It’s really only usually considered if you either know that you have stuck rings, or you have the cylinders off anyway, and find that your piston rings are out of spec. I don’t think that’s very common and ring replacement usually happens with high miles.

Concentrating on the valve clearance check, follow your Factory service manual, get the spreadsheet from Steve, and get to work. He, and many others have written many posts on the forum regarding valve clearance and shim replacement. I can’t help, I have only done it on a 16 valve engine. It’s completely different, no shims. You have to be prepared to find valve clearances that are tighter then spec, requiring thinner shims. Proper sized shims will need to be sourced from somewhere. Sometimes shims can be swapped from one bucket to another to get the required clearance. That clearance and the whole process is detailed in the Factory Service Manual, Clymers, Haynes. I remember reading here that one or another of those may have provided somewhat confusing instructions on what direction the cam lobe should be in relative to the shim/bucket when measuring clearance. Again, not my forté, so I can’t help with the specifics. But you won’t know if your clearances are in spec til you get the cover off and measure them. Now, knowing that once you start the valve clearance checking process, you my very well have to wait for shims to finish it, you’ve got to ask yourself If you really want to start it before the trip. Obviously, your bike won’t make it with the valve cover gasket that’s in there. So, do you just hurry up and replace the gasket and ignore the valve clearance? I wouldn’t.

I don't know the milage on this bike, I have no idea. The odo read 9300 kilometers when I got it, but I doubt thats accurate. But it has been sitting a lot.

I have a hard copy of the clymer manual.

I figure Ill try follow the instructions and if I cant make sense out of it I will ask here.

If the valves clearances isn't within spec I will put it back together and ride it til my shims arrive. Measuring them doesn't take long and if I'm lucky they are fine, and if not I'll order shims and redo it all.

Having the bike sit more would just be sad, I didn't get in as much riding as I had hoped. But I will make sure to do whatever I can during the winter to make the bike run fine for the next season.

[Nessism]

Saw your photos in another thread showing the cork gasket. Do NOT use a torque wrench on that gasket or it will pinch out and leak like hell. Tighten the bolts very lightly. Use a 1/4" drive short handle ratchet wrench if you have one.

Oh, and regarding where the screws go...install all the screws loosely into the various holes but don't screw them in. Then juggle them between holes until they all stick out the same amount. That's how you will know they are in the right hole.


.

[alke46]

Regarding your valve clearances, when you do them it is a good thing to remove each shim and on the underneath side will be a number stamped like this: 2.65 or maybe 2.60. That is the thickness of the shim. Record each intake shim as well as each exhaust shim. After checking the clearances, you will then know if one shim can be used in place of another shim to get the proper clearance.

One more note of importance. When you have removed a shim NEVER, under any circumstance rotate the engine without a shim in a bucket. If necessary, place a coin of the nearest size to a shim into the bucket to rotate the engine.

Also, when you have removed a shim, check to see if the stamped number on it is the actual thickness of the shim by using a micrometer. This will verify proper shim thickness.

Being able to switch shims will save you money when ordering the shim sizes you need.

Hope this helps.

[Rich82GS750TZ]

Noreg
I wrote this last night in the "wrench on" thread, but in an effort to keep all this info related to your leaking valve cover gasket in one place, have pasted most of it below. Before you read this, pay very close attention to what Nessism wrote above. "Do NOT use a torque wrench on that gasket or it will pinch out and leak like hell. Tighten the bolts very lightly. Use a 1/4" drive short handle ratchet wrench if you have one."

If I were you, I would do as he says, I'm only putting this info below because you asked:

Major Disclaimer: I am only slightly more experienced at this than you, only starting seriously working on my bike a little over 2 years ago. As stated before, I have had a few failed attempts at this. I now have 1500 miles on the engine I rebuilt, so the most recent cylinder head cover bolt tightening job has held up for exactly that long. That said:

My Manual suggests a torque for the cylinder head cover bolts of 6.5-7 lb-ft. (your factory manual says 6.5 lb-ft.[09 kg-m], not sure what your Clymer's says.) Because the bigger lb-ft. torque wrench is no good at that low range, use smaller lb-in. wrench, multiply the lb-ft figure x 12 to get lb-in. 6.5 lb-ft. x 12 = 78 lb-in. On my first failed attempt I did not own a torque wrench, bad idea. On my second failed attempt I used 72 lb-in. On my third failed attempt, I used 50 lb-in. My most recent and, so far, successful attempt is at 45 in-lb. You'll have to figure out the conversion to kg-m or N-m if needed. I know there's easy converters on line. Just google it. I am in no way suggesting any of this will work for you. It's what is working for me on my bike right now. (knock on wood, cross my fingers, say a few Hail-Marys). Your home-cut cork gasket (nice work by your wife, by the way), may or may not squish like the OEM gaskets I've used.

As for the various bolt sizes. I should have suggested making yourself a cardboard "map" to place the bolts into as you removed them. Just a tip I picked up watching YouTube videos and probably read it on the forum as well. Now I do it whenever I take any cover off the bike. It's a huge help when putting things back together. Anyway, according to the parts fiche from partsoutlaw, you should have (10) 6 x 35mm long bolts, and (6) 6 x 40mm long bolts for the cover. Where they go, I couldn't say. I'm sure someone else w/ experience w/ an 8v engine can tell you. The 4 bolts for the Breather Cover are much shorter 6 x 25mm, so at least you will have those where you need them. Although you probably didn't take the cover off the top anyway. Good Luck.

[Noreg]

I assembled the motorcycle. I was able to run the bike (with just the gas in the carbs), and there is no visible signs of leakage. I used what felt like a wildly inadequate amount of torque. I used my tiniest ratchet and stopped at the tiniest amount of resistance. Like one finger and when I felt resistance I stopped.

Running the bike on the gas in the carbs for a bit yielded no leaks, so that seems promising. I am knackered from working long shifts this week, so I can't get myself to put on the tank and go for a ride.

So we will have to wait til tomorrow to see if this project was a success.

I realize a short run with cold oil isn't necessarily representative, but when my oil filter cover leaks (like every time I change the filter) it leaks a ton in the first moment. The RPMs was quite low (like 2200), but its cold out so not necessarily unormal.

I noticed sparks in my vacuum tube. Is that normal?

Edit: and thank you all for your suggestions, advice and encouragement. I couldn't have done this without you.

[Noreg]

It does not run right now. When I tried to start it now I got gasoline out of the airbox...

I did struggle to start it at first, and gave it a bit of throttle (I routed the gas line wrong so the choke wouldn't open).

It runs for a bit, sounds a bit off, and then stutter and die. If I hold the throttle open it stays for a while, but gas leaks out.

I am not really sure what to make off this.

The seal does not appear to leak though.

[Noreg]

Just another update. I rode it for 23 kilometers, around the city (like max 70 km/h). No visible signs of oil leak.

I used 1.5mm cork gasket from Biltema. I bought way too much because I bought the same size someone here did, because I didn't realize the picture was after he cut out the right size.

The reason it didn't run was because I put the fuel hose on the vent instead of where it should go.

[Noreg]

Now at 3000 kilometers it appears to be sweating oil. But mostly while standing still on the sidestand with the engine off, strangely enough. By sunday I will have done 2000 more and I have a new gasket at home, but I wonder if I should replace those rubber half moons? Its the left frontmost corner it seems to come oil. When the cylinder head cover is off, that is where the oil leaks out when on the side stand.

At continious high speeds I leak a significant amount of oil through the generator cover. I was going for about an hour at 5-6000 rpm in fifth gear and now the oil level is low.

[Steve]

I noticed sparks in my vacuum tube. Is that normal?

What "vacuum tube:?

We have a few transistors in various areas, but no vacuum tubes of the electrical variety.

.

[Rob S.]

Call a TV repairman, circa 1965.

[Noreg]

What "vacuum tube:?

We have a few transistors in various areas, but no vacuum tubes of the electrical variety.

.

Rubber hose from petcock to cabeurator.

[Brendan W]

Rubber hose from petcock to cabeurator.

When did you see the sparks?
Could your tank be touching a bare wire or even sitting on the coils?

[Noreg]

When did you see the sparks?
Could your tank be touching a bare wire or even sitting on the coils?

when trying to start the bike after misinstalling the gas tank. the sparks was from the carb side. the vacuum tube wasn't attached to the pet cock. Was like flashing inside the tube. Could this have made it brownish?

It very well could be touching a wire or be sitting on the coils.