My gas tank appears to be leaking engine oil

[Guest]

Well I found the leak...

https://i.imgur.com/iDnzqDY.mp4 <- with sound.

 

[Rich82GS750TZ]

Well, you found A leak. Did you ever clean it up, dry it, then spray foot power on the engine to see where other leaks may be? The tach drive seals are a pretty easy fix, just 2 parts you need. One is a flat type of oring with goes on the outside of the shaft that goes in the hole. One is like an oil seal that goes on the inside of the shaft. 23 (26451-45000) and 24 (09289-05002) on the partsoutlaw fiche.

Your pic also shows an eclectic mix of exhaust studs and bolts. That's gonna be fun when you go to remove the exhaust.

 

[Guest]

Well, you found A leak. Did you ever clean it up, dry it, then spray foot power on the engine to see where other leaks may be? The tach drive seals are a pretty easy fix, just 2 parts you need. One is a flat type of oring with goes on the outside of the shaft that goes in the hole. One is like an oil seal that goes on the inside of the shaft. 23 (26451-45000) and 24 (09289-05002) on the partsoutlaw fiche.

Your pic also shows an eclectic mix of exhaust studs and bolts. That's gonna be fun when you go to remove the exhaust.

Did you see the linked video? When I rev it I can visually see the the oil pouring out of that.

The seals for the tach is already ordered and on the way, but like the cam chain tensioner that leak is not an urgent matter. I assume a visible stream of oil at anything higher than idle is. I don't really believe the tach is leaking, but all the rubber is rotten, so I'll replace them anyways.

I think cleaning it and then running it when it leaks this much doesn't make much sense, Ill change the cylinder head gasket (need to cut my own) and fix the tensioner, and then I can go hunting for more leaks.

Video is here: https://i.imgur.com/iDnzqDY.mp4

 

[Rich82GS750TZ]

Oh, sorry, no, I missed video first time looking at your post. You need a new valve cover gasket. That's leaking a lot. I think it's time to park it. But you still need to know if your head and/or base gaskets are leaking as well. You don't want to do all this work and only replace the gaskets that you THINK are leaking, or that are clearly visible at a glance. If you have to, having just done it myself, replacing base and head gaskets isn't is scary as it sounded before I did it. Warning, if you get in that far, you may want to put new rings in as well. You'll get really good at scraping off old gaskets. But I'm getting ahead of myself.

While the valve cover's off, you should do valve clearance check. Lots of posts on the forum about how to measure clearance, and swap out shims. Seek out member Steve and email him for his valve adjustment spreadsheet which will be a big help with the math and show what shims you need in vs. what you have in what locations. Ugh - I feel your pain.

You wrote cylinder head gasket. Are you sure that's what you mean. Video shows valve cover gasket (or more correctly, according to the fiche, Cylinder Head Cover Gasket) leaking. If you need to replace the head gasket because it's leaking, conventional wisdom states to replace base gasket as well, because it's likely to be disturbed when you remove all the bolts that keep the head on the cylinders. I would recommend OEM gaskets all around. Is there a reason you say you have to cut your own?

 

[Guest]

Oh, sorry, no, I missed video first time looking at your post. You need a new valve cover gasket. That's leaking a lot. I think it's time to park it. But you still need to know if your head and/or base gaskets are leaking as well. You don't want to do all this work and only replace the gaskets that you THINK are leaking, or that are clearly visible at a glance. If you have to, having just done it myself, replacing base and head gaskets isn't is scary as it sounded before I did it. Warning, if you get in that far, you may want to put new rings in as well. You'll get really good at scraping off old gaskets. But I'm getting ahead of myself.

While the valve cover's off, you should do valve clearance check. Lots of posts on the forum about how to measure clearance, and swap out shims. Seek out member Steve and email him for his valve adjustment spreadsheet which will be a big help with the math and show what shims you need in vs. what you have in what locations. Ugh - I feel your pain.

I totally agree that I should do all of them, but I have a trip the 7th, and I am running out of season FAST. So I will cut myself a gasket for the head and the breather and fix the tensioner and cross my fingers I can make it to Oslo and back. After that I will probably run out of season in a a few weeks to a month, at that time I will get all the original gaskets and do a full-arsed job.

Rings? What is that refering to? o-rings?

Doing the valve clearance check is something I've been putting off, but I am excited about it, when I'm there anyways I should just do it. I also have new stainless bolts for the top. Then its just the front bolts and the cam chain left.

I really want to get done with the top ten newbie mistakes list. But I dread dealing with the gas tank...

Edit: Also if the previous owner used some low quality gaskets, they are living on borrowed time anyways, and Id probably be best off getting OEM for it all.

 

[Rich82GS750TZ]

Rings= Piston Rings

 

[Guest]

Rings= Piston Rings

Ahh, I guess that makes sense. Anything else that... Err, if I am going to do that, I need the exhaust bolts out? Definitively a winter project.

I have never cut a gasket before, I am really curious of how it will turn out. I have the cork gasket kind that I saw someone else use here. My new gasket is supposed to be shipped the day I leave.

I also wonder if the rubber boots for the air box needs to be replaced, they are HARD to fit on the carbs (or I have unusually weak fingers).

But dealing with it all during the winter means next season will be great. Perfectly working bike from day one.

 

[Rich82GS750TZ]

You're a braver man than I. Having never cut a gasket, doing so and then taking a long trip is not something I would attempt. What I do know is that my first 3 attempts at properly tightening the valve cover bolts resulted in me over torquing the bolts and the gasket squished too mush and ripped. I got more and more mile before a leak each on each successive try. I'm on about 600 miles since I did it last so I think I'm getting the hang of it (knock on wood).

 

[Guest]

You're a braver man than I. Having never cut a gasket, doing so and then taking a long trip is not something I would attempt. What I do know is that my first 3 attempts at properly tightening the valve cover bolts resulted in me over torquing the bolts and the gasket squished too mush and ripped. I got more and more mile before a leak each on each successive try. I'm on about 600 miles since I did it last so I think I'm getting the hang of it (knock on wood).

That sounds a lot harder than Id imagine. Ill use the torque wrench.

I have road side assistance and I could always take a train or hitch hike down if I have troubles (pick bike up with trailer later).

If I get the head off tomorrow I can have the gasket ready before the weekend and test ride it in the weekend. I've been wanting to do a run down Sweden.

And if nothing works I guess Ill have to use the car, but that would be boring.

 

[Rich82GS750TZ]

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.

 

[Guest]

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 fort?, 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.

 

[Guest]

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 fort?, 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.

 

[Guest]

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.

 

[Guest]

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.

 

[Guest]

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.

 

[Guest]

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.