Top End Tear Down

[Guest]

Hi I am disassembling the top end of my 79 GS1000 (built in 78) to replace my base gasket. Does anyone have any thoughts on the bare minimum maintenance that I should do to the engine in this state. How about tips for the strip down and rebuild. Finally, any suggestions on items that are not to ambitious to enhance the engine while keeping its reliability.

[Nessism]

Replace valve stem seals and only use OEM Suzuki gaskets.

[cowboyup3371]

Take careful stock of where you put parts and how you install them so you don't tear anything. Especially don't plan on moving during the process unless you like losing them...

[JTGS850GL]

You may consider lapping the valves as well. Many things are MUCH easier with the head and jugs off. Here's a list I can think of:

New base and head gaskets. OEM only.

New valve stem seals.

Check valve springs, retainers and locks. Replace as needed

Lap valves or valve job if needed.

New rings

Hone cylinders

If cylinders are scored then pistons and a rebore are in order.

Cleanup mill head and cylinder deck. Remove MINUMUM material to make it straight. Too much material and you may have to shave a mm off the valve stems.

Rebuild cam chain tensioner

New valve cover and breather gasket as needed

Again, it all comes down to what condition your engine is in before the tear down and how long you intend to keep it.

[Nessism]

Cleanup mill head and cylinder deck. Remove MINUMUM material to make it straight. Too much material and you may have to shave a mm off the valve stems.

Sorry to pick but believe this is incorrect. Decking has no effect on valve clearance (shaving the valve stems).

[1_v8_merc]

Make sure you order the oil O-rings. Not all gasket kits will supply them.


There's a long Rectagular O-ring that fits around the Cam-Chain area. It sandwiches between the cylinder jug and head.
Theres also One or Two oil port O-rings, that sit in the corners of the heads.

[HaggisHombre]

Great advice. The bike did not run to well when I got it home but I believe that was due to the carbs and the junk in them. It was not smoking and the compression was within limits. I wanted to strip the engine before ordering gaskets and from what I heard that was a good thing. From what was said here is the minimum that I will be doing. OEM gaskets, valve stem seals, re-seat the valves, clean of course, and other things as needed like piston rings. The bike has 26000 miles on it. I am doning a complete refurbish. I have lots of other parts for it like K&N filters, jet kit, 4 into 1 E-ignition, etc.

[chuck hahn]

Check the cylinder wear per the service manual and maybe run a hone to freshen the walls a bit. May as well put in new rings as the engine is fully apart now. Check wrist pin wear. Decarbon the piston tops and the head can be soda blasted to remove the crap. Recut the valve seats. In other words..do a complete top end refurb ( I would if I had the jugs off an engine).

[JTGS850GL]

He's asking bare minimum, not whole hog spend em while you got em top dollar remanufacturing.

If it was running fine before the gaskets it will run fine after. If it wasn't he will need more work. He said he was replacing the base gasket, this would imply it was running fine.

The point being that the "bare minimum" depends on the current condition of the engine and what you find when the cylinders are off. Replacing the base gasket says the cylinders are off and a great time to do some cheap insurance work. The list above simply was a check list to choose from depending on what you find once everything is off.

Sorry to pick but believe this is incorrect. Decking has no effect on valve clearance (shaving the valve stems).

Yep, you're right. The valve height issue would be if doing a valve job and cutting the valves deeper. Not cutting the deck or heads. That would only effect compression and piston to valve clearance. Typing too quickly while trying to get out the door to work. Sorry for the confusion.

[JTGS850GL]

Great advice. The bike did not run to well when I got it home but I believe that was due to the carbs and the junk in them. It was not smoking and the compression was within limits. I wanted to strip the engine before ordering gaskets and from what I heard that was a good thing. From what was said here is the minimum that I will be doing. OEM gaskets, valve stem seals, re-seat the valves, clean of course, and other things as needed like piston rings. The bike has 26000 miles on it. I am doning a complete refurbish. I have lots of other parts for it like K&N filters, jet kit, 4 into 1 E-ignition, etc.

Sounds to me like you're on the right track. Take the engine down first. Let what you see and measure determine what is needed. No one here can tell you definitively what is needed until then.

[HaggisHombre]

Yes I see where you are coming from chuck.

I was about to remove the camshafts when I realized the manual does not explain that very well. I understand the bit about holding the camshaft with vice grips but how do you then disconnect the allen bolts that hold both parts together, then remove them from the chain?

[azr]

You remove one cam shaft at a time. Hold the cam shaft in place with vice grips. Undo and remove all the cam holders for that cam shaft. MAKE SURE you loosen the 4 bolts for each cam holder in a pattern, do not just take one out at a time. You can easily strip the bolts/head that way. It's the same when you go to put them back in. The covers can be a bit snug but a simple pry with a flat head screwdriver will pop them up.

[Nessism]

With only 26k on the engine you shouldn't have to do anything to the valves other than clean and lap them. Each valve should stay in it's original hole so mark everything appropriately. Of course, if the previous owner didn't adjust the valves they could burn, so inspect everything carefully. Hopefully that won't be the case though.

If you decide to replace the rings you should use a bottle brush hone to clean up the bore, not a straight hone. 240-320 grit is the appropriate type.

Good luck

[HaggisHombre]

Ok great back to the garage to remove the cams. Thank you.

[HaggisHombre]

Got the cams off no problem, and the shims are out. Now I need to figure out the order to loosen the cylinder head bolts.