Help with GS1000E Service

[Guest]

I'v got an oil leak on my '79 GS1000E. It's showing up on the front of the cylinders and from searching and reading here I've got at least three things to look for, tack seal, head bolt o-rings, and cam chain tensioner.

I have about 13K miles and the valves have not ever been inspected so I was already planning to inspect and adjust the valves. I had bought a stock valve cover gasket and breather cover gasket, but after doing some reading, I'm wondering if I should buy the rubber valve cover gasket instead.

Would I be better off get the rubber gasket?



I didn't buy the half moon plugs originally, but now I think I should go ahead and replace the 30 year old plugs while I'm in there.

I've got that part number as 471240-001 - Plug Cylinder H



I'm hoping that my oil leak is the tach drive cable seal. I'm planning to go ahead and replace it on this service.

I've got the following part numbers.

490260-001 - Seal Band
472446-001 - Oil Seal
490250-001 - Drive Gear (if necessary)



So I've read about another common source of oil leaking and that's the o-rings on two of the head bolts. I think it is the front inner bolts on studs number 1 and 3? I've read that while it may be best to pull all the head bolts and replace the head gasket, it is possible to replace them one at a time without any risk to the head. With a stock virgin motor and only 13k, I'd like to avoid pulling the head if this will work.

I'm wondering if this is something I should just plan to do anyway, or not replace them unless I can determine they are the source of my leak?

I haven't been able to figure out the part numbers for these o-rings yet. I was looking at the schematics at Bike Bandit, but I'll look more here and check another site with a schematic and also look at my service manual. I'd appreciate any insight on these part numbers.

Last thing is I think I remember another possible source of oil leaking and appearing on the front of the cylinder to be the cam chain tensioner. I'm still reading up on this and wondering if I should go ahead and inspect it and replace the gasket and o-rings on this service.

I've got the GS1000E gasket part number as 480123-001 - GKT Tensioner A

The following parts came from bwringer's tutorials (Thanks BassCliff!)

Small o-ring for the lock screw.
Suzuki Part No. 09280-06005

Large o-ring that goes at the base of the threads for the large cap nut.
Suzuki Part No. 09280-21013

Oil seal, Suzuki Part No. 09284-10006




I'm going to try and leave the carbs installed since I removed them and cleaned and installed rebuild kits in them last summer. I didn't replace any of the boots or o-rings and I know now I should have, but it was really running good last year, so I'm going to save that for later. I kept the stock airbox and it was really a pain to remove and re-install the carbs. Maybe I'll go with pods when I get into the carbs again, and replace the stock pipes and re-jet, but that's hopefully a project for next winter!

I did just buy a CarbTune and want to sync the carbs, so I may go ahead and do that while the tank is off.



Is there anything else that I should consider while I have the valve cover off and I'm trying to fix the oil leak and do any preventative maintenance in that area?

Thanks for all who have given so much here. I've trying to use the search feature and learn all I can to get my 1000 back in top condition. My goal is to have it running well in time for the SE gathering in June.

Thanks!
James <><

[almarconi]

If you haven't done it yet, I would clean the engine off really good and then apply some powder and see if you can see where it is leaking from.

If the valves have not been adjusted its a good idea to check them. The stock oem gasket is fine.

[GaThumper]

If you haven't done it yet, I would clean the engine off really good and then apply some powder and see if you can see where it is leaking from.

If the valves have not been adjusted its a good idea to check them. The stock oem gasket is fine.

Thanks! A good cleaning and inspection is my first order of business. I'm just thinking that I should go ahead and replace all the potential problem seals, gaskets, and o-rings rather than wait for them to fail. Some 30 year old parts just need to be replaced. I wish I had done the carb boots and o-rings when I serviced the carbs!

[knotzilla]

You forgot the square O ring for the cam chain opening. This O ring is known for getting hard and brittle, Ted

[GaThumper]

You forgot the square O ring for the cam chain opening. This O ring is known for getting hard and brittle, Ted

Thanks Ted! Is this o-ring on the top of the head or between the head and cylinder? I don't see it on the head schematic at Bike Bandit.

Edit: it's under the head and I hope not to pull the head this time.

At this point I'm not planning on pulling the head. There is a difference of opinion on whether I can replace the head bolt o-rings without pulling the head. I remember reading one post that said you could if you just pull them one at a time there was no problem, and other posts said you would need to pull the head. I'm still ressearching and not sure yet if this is part of my problem or not, just planning to replace them if I can anyway without pulling the head, or if that's where the leak appears to be, I'll go ahead and do what is necessary!

Thanks Again!
James

[knotzilla]

It's between the head and cylinder and fits in the head gasket. If your head/cylinder mating surfaces are pitted and your square O ring is hard then there is a good chance that is where the leak is coming from. That was the case with the oil leak I had. Since I had 80,000 Km on my bike it was cheaper to buy a complete used head and cylinder block with pistons then to have the mating surfaces machined. Ted

[GaThumper]

It's between the head and cylinder and fits in the head gasket. If your head/cylinder mating surfaces are pitted and your square O ring is hard then there is a good chance that is where the leak is coming from. That was the case with the oil leak I had. Since I had 80,000 Km on my bike it was cheaper to buy a complete used head and cylinder block with pistons then to have the mating surfaces machined. Ted

Thanks again Ted! I'm hoping not to require going below the valve cover this time. My bike has only 13k on it and is in good condition other than the small oil leak. I'll clean and inspect this weekend and may find it's only the tach cable or cam tensioner!

[GaThumper]

OK, the BIG question now is "Does the '79 GS1000E have the o-ring seals under the center head bolt/nuts?

I was unable to find them on the schematic for the '79 GS1000E as seen here from Alpha Sports.



But I did find a thread referencing them as number 17 on this schematic for the 1983 GS1100E.

[hampshirehog]

The 79 1000 does not have any rubber seals under the centre head nuts. On some aftermarket head gaskets there are separate O rings that sit inside the gasket on the outer studs - where the number 7 is pointing on the top diagram.

[GaThumper]

The 79 1000 does not have any rubber seals under the centre head nuts. On some aftermarket head gaskets there are separate O rings that sit inside the gasket on the outer studs - where the number 7 is pointing on the top diagram.

Cool! Thanks for the confirmation. That's one less thing I have to worry about now. So, I'm still hoping that the oil is coming from the tach drive o-ring. A good cleaning and observation and I hope to be able to confirm this weekend.

Thanks,
James <><

[GaThumper]

OK, to summarize here is the list of parts I'm going to order Monday. Does this look correct? Anything I'm missing?

I'm going to stick with the stock valve cover gasket since I've already bought it. I've seen to grease it on both sides and I've seen to grease it only on the head side. Any thoughts?


Half Moon shaped cylinder plugs

471240-001 Plug Cylinder H - qty 4


Tach Drive cable seal

490260-001 - Seal Band
472446-001 - Oil Seal
490250-001 - Drive Gear (if necessary)


Cam Chain Tensioner

480123-001 - GKT Tensioner A

Small o-ring for the lock screw.
Suzuki Part No. 09280-06005

Large o-ring that goes at the base of the threads for the large cap nut.
Suzuki Part No. 09280-21013

Oil seal, Suzuki Part No. 09284-10006

Thanks Again!
James