Ok,

So I have my gasket set and my manuals.  Replacing gaskets is not one of the major points covered in the manuals.  Could someone walk me through the basics of replacing the base gasket?  Do I have to take off the gas tank?  Does the engine need to come out of the frame?  Do I use some sort of gasket sealer?  If so, what?

Don't assume that the writer of this question has any degree of mechanical knowledge, experience, or aptitude.  All I've got is a bike, a set of tools, and a couple of manuals.

Thanks,

El Noobo

The valve cover, cams, head, and cylinders have to be removed. These are all covered in every service manual I have seen. I learned by following the service manuals.

No sealant is required, the base gaskets has a painted surface as sealant. Gas tank has to be removed. Engine can stay in the frame.

Thank you.  I guess I should not be looking for "how to replace the base gasket" in the index of my service manuals.  Perhaps one day I will have banged together enough experience to write a GS500 Service Manual for Complete Incompetents   

It should be listed under removing the top end.

It's not that hard.  The manual will have step by step directions in the 'Engine' chapter.

Cool.  Thanks.  So far, I've been doing piddlin' stuff to the bike.  Actually getting into the engine is a little intimidating, but I'm sure I'll get the hang of it.

Base gasket was the first job I did on my GS it leaked like the Exxon Valdez and I used the fact to get a chunk off the asking price.  You are gonna need a good torque wrench, always work to mid range of the quoted figures to allow for any inaccuracies with the wrench. A Piston ring clamp would also be handy as would a big soft mallet to help loosen parts off. Things to be careful of....dont drop the timing chain into the case, dont let the pistons drop against the case when you lift the cylinder off, the sides might get dinged and be very careful when removing the header bolts as they are prone to shearing. Pack the case openings with rags to prevent any sh** getting in there and clogging oil-galleries when the cylinder is off. Re-tighten the headbolts following the diagonal pattern to prevent distortion and use the genuine Suzuki gasket set, some cheap pattern ones are of dubious quality. Before you start to dismantle it check you are familiar with and understand the timing marks and disconect and remove the battery. Most important thing though is to read the manual and be sure you understand it. The job is not difficult if you follow it, use good quality tools, keep everything clean and dont force anything. Take your time, you will enjoy doing it.

I just looked over the manual and it really shouldn't be that hard. You'll want to get some ring compressors (the type that can be dissasembled) and some moly assembly lube before you get started. If you can't find any ring compressors, some hose clamps and brass sheet metal should work, but will be a pain. Also check your valve clearances before you remove the cams, you'll be able to adjust the clearance without the special tool once the cams are off. The hardest part will be timing the cams once it's all back together.

Let me know when you're about to get started, I can help out, or at least drink beer and watch  The whole thing can be done in a day, or a couple evenings.
good luck 

Ring compressors are not required. The sleeves have tapers to allow the rings & pistons to be pressed in by hand. Stock diameter sleeves are easy to work with. But 78 and 79mm bores are a pain.