1980 GS850 Head Gasket Replacement

[kdchart]

Finally Started Head Gasket Replacement

I finally started tearing into the bike on Friday night. I've got everything cleaned, sorted and ready to go back together. Everything looked pretty good internally, I could not find anything that looked broken or worn. (Bike has 26,000 miles).

The carb intake boots are hard and stiff and the engine intake boots are starting to separate from the metal flange (both need replacement I think).

I'm going to hone the cylinders tomorrow and get some help to put it back together.

I think the bike (1980 GS850G) has different points than the original. They look electronic rather than gap swithes. (not sure what they are called) It looks like the timing is more "fixed" with these points.

Is moly a requirement when putting the cams back together? (I think my buddy has some)

This whole tear down and gasket clean up took a LONG time for me. Other than that, I hope I put it back together right, the gaskets hold, and it runs like it used to.

I'll keep sending updates (hopefully good ones).

Later - Kevin

[kdchart]

Lock-tight?

Where are the most common places to use lock tight when re-assembling?

My head is swimming with misc helpfull hints I'm trying to remember.

[kdchart]

Finished - She came to life

After months of searching, reading, and waiting on parts, I finally finished the head gasket, base gasket, valve seals, and piston ring replacement. Here is a quick run-down on the job. I do not have a digital camera so you have to read (I'm stuck in the 80's)

First off - Many thanks go to bwringer for taking an interest and giving the support for the job (thank god for this site and the good folk that frequent it).

Tear down went pretty well. I started on a Friday night and actually spent the whole night with the bike. Took rest at 6:00 AM. The next night I got to scraping off the old base gasket and vigilled through it as well. I would definitely recommend purchasing the BEST gasket stripper known to man BEFORE starting the job. Wall-Mart in Alaska does not carry it. Luckily I had some paint stripper at home and read that it may do the same thing. Lots of time.

I also replace the valve seals even though they did not look to bad (not that I knew that at the time, but what's a couple of hours between you and your ride). In the middle of the night (while waiting for the paint stripper to take effect), I was sort of forced to custom make a valve compressor from one that was not designed for motorcycles. I bought one from Sears but it did not work. I ended up grinding a window out of a 7/8" socket to make it work. It did not work all that well, but I got through it.

By Sunday morning, I was ready to put things back together. That's ~ 20 hours into this project. Better valve compressor and gasket remover would have help immensely.

Re-Assembly went pretty well. I replaced the rings, even though the clearances looked pretty good on the cylinders. I cut two pieces of wood like the Clymer manual recommends for piston #2 and 3 to hold them in place. I also used hose clamps to compress the rings. This all went well. I did a hand hone of the cylinders to take the glaze off.

Everything else went pretty much like clockwork. I ran the bike for 10-15 minutes, and then changed the oil. I'm also in the process of taking the Vetter fairing off and installing a headlight (that I have not got in yet), so have not put more than 20 miles on it so far.

From what I can tell, it runs as good as or better than before even though I have not taken it above 4000 rpm. So far no oil leak!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!

This bike had 25,000 miles on it and I think I'm the third owner. From what I could tell, all of the internals were in perfect running order, but I'm not sure what work was done to it in the past. It definitely needs new intake boots and carb intakes. I did replace the screws with 5mm alien head bolts.

In the process of replacing the faring, I had to take the front forks off. This was pretty easy after the engine re-build.

Once again, many thanks bwringer and to this site for the back-up information. I used the Clymer manual coupled with the factory manual for the step by step, but I think the Clymer would have been just as good alone.

I'm still waiting on parts (headlight), so I would recommend ordering everything you need up front and not delaying anything.

I hope you can all keep-em running. They're fun to ride
.:-D

Later - kdchart

[cberkeley]

Hmmmmm....... This has been excellent reading indeed. I have to do this on my GS650GL at some point and this has inspired a lot of confidence. Who is a good supplier for rings?
Thanks folks, Cletus\\/

[kdchart]

Head Gasket - Piston Rings

I have not loged on for a while. This may be too late but....

I simply ordered the rings from Bike Bandit.com. These were factory Suzuki from what I could tell from the packaging. I guess you would need to know if your bike has had any internal work done on the cylinders or not (oversized). They cost about $100 for the complete set.

By the way - The bike has a lot more response to the throttle than it had before. It was good to make the change. I have not checked the compression to see the difference.

Good Luck - Kevin

[rcarteraz]

Hi, I'm in a middle of replacing my base gasket. My question has to do with the pistons. The pistons have a little scoring on one side. The manual tells me to change all the pistons. The pistons look okay except for that and are within dimensional tolorance. Can I reuse the pistons? My bike has 25,000 miles on it 1981 GS850GX

[bwringer]

Hi, I'm in a middle of replacing my base gasket. My question has to do with the pistons. The pistons have a little scoring on one side. The manual tells me to change all the pistons. The pistons look okay except for that and are within dimensional tolorance. Can I reuse the pistons? My bike has 25,000 miles on it 1981 GS850GX

25,000 miles is nothing to these engines. The pistons won't look factory pristine, but they'll work just fine. Put 'em back in.

Scoring means vertical grooves that catch your thumbnail, and visibly missing metal. It's abnormal wear from foreign matter that's very unlikely to look the same on all four pistons.

The light scuffing you're probably looking at feels fairly smooth and is harmless and normal.