1980 GS850 Head Gasket Replacement

[kdchart]

I've got a leak, and don't want to pay a grand to have the shop fix it. I've been reading quite a few messages, have the manuals, and ammassed a few tools. I'll start by re-torquing the nuts, but don't have much faith.

1) When I changed the oil, I think I over filled it in one of two ways. A) I had in on the stand and it was good, but the bike tilts foward a little on the stand. When it's level, the oil level was too high. B) I may not have warmed the oil enough before changing and it did not drain out completely. Not sure. If the oil is too full, will you ruin the head gasket?

2) Gaskets - Is bikebandit.com an OK place to order them from or do you have better ideas?

3) Gaskets - I think I need the head gasket, a rectangular O-ring at the joint, and a head cover gasket. Does that about cover it?

4) Valve Shim Adjustment - I have no source of local shims. The bike seems fine now, will changing the head gasket effect the clearence (I don't think so, but not sure)? If I need a shim, would I need another valve cover gasket if I put it back-together and run it until the shim(s) comes in? Do you need to change the valve cover gasket every time you check the valve clearences?

5) Any idea of the parts I should have on hand before starting?

Thanks - Kevin

[Guy]

It's unlikely that overfilling with oil would cause your head gasket to blow. It might sweat around the base gasket or blow a bit through the breather though. Are you sure the leak's from the head gasket and not the cover gasket? If your going to the trouble of lifting the head buy a 'top set' for the engine. It includes head gasket, cover gasket, base gasket (which hopefully you won't need if your careful), exhaust gaskets and valve stem seals. (You might as well do these if the head's off). As for reusing the cover gasket, smear it with a little grease before you install it and it'll come away easy within a couple of thousand miles or so. If you haven't done it before allow a weekend for yourself, and be extra careful with your valve timing!

[bwringer]

If you're taking the head off, you definitely should replace the base gasket. Some have gotten away with it, but many are running around with leaky base gaskets wishing they had completed the job properly. That 26 year old gasket will be as hard as a rock and very brittle by now. It will most likely crack with the slightest movement of the block when you remove the head.

The Vesrah gasket kits are very nice, high quality stuff. The Athena kits you see on eBay are crap. There are a lot of other bits in the kit you'll need, such as valve seals, new copper washers, exhaust seals, etc. You'll also get case and oil pan gaskets (a top end only set is not available for a GS850), but it's still far cheaper than buying everything seperately. I think the Vesrah gaskets are actually better than the OEM Suzuki, but others might disagree.

You can get them here:

http://www.z1enterprises.com/

http://www.crc2onlinecatalog.com/

Be aware that these kits are still not really "complete" -- for some unknown reason they do not include intake boot o-rings, seals for the tach drive, or the gasket, or-rings, and seal needed for the cam chain tensioner. They are also missing all the seals and o-rings needed for the bottom end of the engine -- they only include clutch, alternator, and oil pan gaskets.

[kdchart]

Going down to the base gasket is a lot more complex. I would need to take the pistons out of the cylinders. I need to read a lot more in the manual before even knowing what all of my questions would be at that stage.

What are the main tools required to get to this level of a tear down?

I looked up the gasket kits - Thanks

All of the other parts mentioned are ordered one off? Same reference?

[Road_Clam]

I just did a top end gasket replacement about a 2 months ago. (My head gasket also started weeping). All in all not to bad of a job. I have a fair amount of motorcycle expereince. I also had a good friend who offered some Suzuki specific tech guidance along the way. I don't recommend you tackle a top end unless your VERY comfortable mechanically. Do yourself a big favor and do a compression test FIRST to get an idea of the condition of the rings. It's foolish to replace just the gaskets on an engine that has 25,000 mi, and is reading low compression. You should at that point consider piston rings, and a cylinder hone. How many mi. are on your bike? Mine had 17K, and luckily I had 145 psi of compression across all 4 cyl, and my pistons looked in perfect condition. I would have to say the biggest problem I had was fitting the cylinder on to the pistons. This is a job that would have been WAY easier with an extra set of hands!!! Good luck,
Rich

[kdchart]

I'll check the compression with my "new " guage. I must admit I'm a little nervi. The manuals, showed using a hose clamp to assist with inserting the pistons. I'm not sure how that works with the screw attachement on the clamp.

Overall I understand what needs to be done, but my limited access to parts scares me a little.

Thanks - Kevin

[Billy Ricks]

I'll check the compression with my "new " guage. I must admit I'm a little nervi. The manuals, showed using a hose clamp to assist with inserting the pistons. I'm not sure how that works with the screw attachement on the clamp.

Overall I understand what needs to be done, but my limited access to parts scares me a little.

Thanks - Kevin

I've used large zip ties to squeeze the rings with good luck.

[HobieSun]

The hose clamp on the piston is to keep the piston rings compressed. You won't be putting the clamp into the cylinder. You just have to get it close, and slip the piston into the cylinder and then take the clamp off. You will see what I mean if you get that far. Take your time, keep bolts and nuts labeled in a zip lock so you don't forget where they go, write down notes when you are taking stuff apart and you will be fine.

[bwringer]

Going down to the base gasket is a lot more complex.

No, it's not complicated at all. And it's the only way to do a complete job.

There are no more fasteners to remove -- you just pull upwards and slowly work the block off the pistons.

It does take more time because you'll need to scrape off the hardened old base gasket, and also remove the large thin o-rings around the cylinder liners. Once you see how deteriorated these are, you'll be glad you did it right. There are two pear-shaped o-rings that are also critical.

The cylinder block is simply clamped between the head and the bottom end. If it moves the slightest fraction of a millimeter while you're removing the head, the hardened and deteriorated old base gaskets and o-rings will leak profusely. And it's impossible to remove the head and guarantee that the block doesn't also move. Just releasing the clamping pressure could be enough movement to destroy the seal.

The bottoms of the cylinder liners are chamfered so that it's relatively easy to squeeze the rings together and get the pistons started in their bores. Get 2 and 3 started, then 1 and 4. I've never gotten ring compressors, hose clamps, or zip ties to actually work -- I've always ended up simply squeezing and guiding the rings with my fingers. Use plenty of oil, never force anything, and try to get another set of hands to help.

If compression is good and mileage low, you may very likely get away without replacing the rings, especially if you can lightly flex-hone the bores. It's a bit of a gamble -- I'd prefer to install new rings.

[Road_Clam]

I also simply used my fingers to compress 1 ring at a time. This is where I comment "another set of hands" would be a BIG help. My arms started to quickly get tired trying to support the cyl. assembly, and at the same time, carefully start the top piston(s) rings up into the bores. Once I got 2 pistons started, it was easier as I didn't have to hold the cyl.

[kdchart]

OK I think I'm getting up to speed. Here's how I see this going down... I will no doubt be following the manual, but here is a very high level....

I've got 25K Miles on this engine

Remove tank/spark plugs
Check compression
Remove Carbs
Remove tach cable and cam tensioner
Remove breather cover/cam shaft cover/came shafts
Remove cylinder head (leave valves pretty much alone)
Remove cyliner

Replace lower gasket, plus 4 O-rings on cylinder liners, and 2 triangular O-rings
Replace Rings on pistons

Set cylinder back in place 2-3 first then 1-4 with assistance and hose clamps or fingers

Replace cylinder head gasket and rectangular O-ring

Set cylinder head back in place
Replace Tach seal and intake boot O-rings
Replace cam tensioner gasket and O-rings
Install cam shafts and chain while keeping the timing correct
Check Valve clearances and timing / points

Install cylinder head cover
Replace breather gasket and breather

Check compression

Install carbs
Install tank

I don't need to remove the pistons from the drive shaft and I don't need to press out the valves. (Essentially assuming these are OK)

TOOLS
feeler gauge
compression tester
torque wrench
lock tight
hose clamp(s)
screwdrivers
wrenches

PARTS - This is where I need your help......

29: O RING,INTAKE P 472081-001
$1.19 4 each – fuel air intake BB.com

21: SEAL BAND 490260-001
$2.62 1 each – Tach Seal - BB.com

20: CHAIN TENS AD O [2] 471970-001
$0.67 1 each – Tensioner O-ring - BB.com

22: GASKET,TENS ADJ 480122-001
$1.55 1 each – Tensioner Gasket - BB.com

25-1: RING SET, PISTO 478503-001
$24.2 4 each - BB.com

Gasket Kit
Gasket Set - Suzuki GS850 (79-81) Complete Set
SU608-440
Sudco
Vesrah
- - - - - - - - Temporarily out of stock
Complete Gasket Set for the Suzuki GS850GN/GT/GLT/GX 4-cylinder motorcycles. Comprises of the following gaskets: Cylinder Head Cover (1) Breather Cover (1) Cylinder Head (1) Cam Chain O-ring (1) Gasket Washer (4) Cylinder Base (1) Cylinder Sleeve O-ring (4) Cylinder Base O-ring (2) Valve Stem Seal (8) Exhaust Pipe Gasket (4) Clutch Cover (1) Contact Breaker Cover (1) Generator Cover (1) Oil Pan (1)
$66.07 - z1enterprises

I'm not sure where I use the valve stem seals unless I remove the valves (not planned and still not sure) and I could not find a part that looks like a cam chain tensioner seal (Just the O-ring and gasket)?


I know this is a lot of info, but I want to make sure I'm not missing anything huge and have the parts I need before starting.

Any feedback is greatly appreciated.

Thanks – Kevin

[kdchart]

I just received the gasket kit and expect to have all of the other o-rings in a couple of days. Decided to replace the rings since compression was 120-125 on all cylinders. I picked up a 24$ valve compression tool from Sears, so can replace the valve seals.

Thanks for all the advice. I'll share any questions that come up and keep posting any highlights.

Kevin

[Poot]

I just finished doing this on my '80 850, with 62000km on it.

mine was a bit of a nightmare , but it shouldn't be so bad.


Some things to get:

Honda combustion chamber cleaner (or called something like that). you can clean the chamber pretty good.
1: stuff newspapers on top of the shims/buckets so they dont fall out,.
2: put in old sparkplugs
3: turn your cylinder head upside down.
4: fill the 4 depressions with cleaner for 10 min
5: use a brush to clean off carbon deposits.


You dont necessarily have to redo the valve seals. a way to check, is to pour gasoline into the intake and outake, and see how long it takes to seep through. you should at least get to a minute. mine did not leak at all.

Gasket remover . Helps prep to remove stuck on head +base gaskets.

600 grit sandpaper. You must use this with a completely flat surface (metal block, or something) and it will help remove the headgasket remnants, if necessary.

flat razor , to remove old gasket bits. be very, very careful not to gouge.

6pack (brand of choice)


gotta run, hope this helps.

[Big N daft]

I just received the gasket kit and expect to have all of the other o-rings in a couple of days. Decided to replace the rings since compression was 120-125 on all cylinders. I picked up a 24$ valve compression tool from Sears, so can replace the valve seals.

Thanks for all the advice. I'll share any questions that come up and keep posting any highlights.

Kevin

Have to say that if I'd been getting 120-125 on all four cylinders I'd have waited to see what the state of the rings were before I paid out for new ones. That reading is within spec on an old engine and I'd want to see the state of the barrels before deciding whether it would just take something simple like new rings or a decoke of the valves to get compression back to optimum. Hopefully you'll just need the rings

[dodger1]

Did my 850 top end when I rescued it. 70,000 km (call it 45K miles?) Re-ringed it just to be safe, light hone with a hand drill and brake cyl. hone I happened to have. Bought the factory gasket set 'cause it was available from a friendly dealer at the time - it did include the pear-shaped o-rings, as well as the base gasket,barrel o-rings, and copper washers. This was made easier for me as I got the factory manual and I gotta agree with having a second pair of hands available to help drop the block over the pistons. I didn't, used hose clamps, worked well enough. (But I rushed it and wound up with a broken top ring!!) What ever you decide, do make sure you have ALL the necessary gaskets on hand, do the base gaskets as mentioned, and TAKE YOUR TIME!!! As for the valve cover gasket, spray it with WD-40 liberally before installing, you'll be able to re-use it a few times. bwringer describes the whole procedure better than I can, just want to assure you you can do it, it ain't rocket science. Have fun!!