Replacing head gasket 80 gs850

[eil]

Rings are around $25 per cylinder for the 850 last I looked. So not an inconsiderable expense. I'm of the opinion that if the rings and cylinders still measure within spec, then there's no need to re-ring and hone--the parts are worn in as they should be and still plenty good. Especially our hard-to-kill 8-valve shafties. Merely disassembling the engine doesn't automatically make them bad. But there are others who see it as a necessary step any time any engine is taken apart for whatever reason. To each their own.

[Wingsconsin]

A weekend at Steve's and this happened --

When I bought my new-to-me GS850 it had a few leaks. I managed to get it running and stopping but it seemed to need several new seals and gaskets to stop the oil from dripping in several places. Steve (being a good friend) invited me to bring the bike down for a long weekend and we (HE mostly) would strip it down to the base gasket and get it right. The bike had about 32,000 miles on it and we re-assembled it with the same rings after cleaning and lightly honing the cylinders, replacing valve seals and generally cleaning and refreshing everything we could get to...
Pictures follow --

[520eek]

So how did the engine performance turn out after it was all said and done? And.... I am thinking that new rings won't hurt and are super easy to install at that point. The biggest concern now is getting the valve guide seals installed... I will be asking a couple friends if they have the tool needed to get springs off and the new seals installed.

[JTGS850GL]

To get the springs off I use a large C-clamp and a cheap O2 socket with the slot widened. Some use PVC pipe and put a slot in it. Either way. Not very hard to make and fairly easy to use. The only problem I've had with getting the valve stem seals replace was getting those darn old ones off. Takes a lot of pulling twisting and turning to get them to come loose. Seems like the exhaust seals are harder to get off. Probably due to heat hardening.

[Wingsconsin]

It ran (pretty **** poor) before Steve and I did the re-do. The carbs were a mess, and I did those BEFORE we tore it down and it got better.
Then after the re-do it was carb synched, valves done, etc, etc, and it runs perfect now... I average 42 MPG city commuting (purpose specific bike for me)
And it goes fast - doesn't leak (like it did before) and runs smooth - the 850 is an amazing power plant in my opinion.
I will be re-checking the valves soon in spring, re-tourqueing the head bolts while I have it open, and re-synching the carbs.
I feel the bike ie running 'just a tad' rich and might tweak the carbs as well..
It starts easily (even after a winter layoff) and warms up and runs great.
I feel I have a bike I can own and ride for a VERY long time to come with this one...

[520eek]

Duh.... c-clamps.....I am still in a morning fog!

Thats good news to hear about the finished results after the tear down/reassembly

[520eek]

Hey wingsconsin... was the base gasket a real chore to get off for that project or did you luck out?

[Steve]

To get the springs off I use a large C-clamp and a cheap O2 socket with the slot widened. Some use PVC pipe and put a slot in it.

I have given up on the PVC pipe and am now using a 24mm deep socket with a window cut on one side.

It probably looks a lot like your O2 socket, but I did not know about them when I was shopping.

.

[Wingsconsin]

Hey wingsconsin... was the base gasket a real chore to get off for that project or did you luck out?

Every gasket was stuck on pretty hard... Steve did the seals, and honing, and technical work of every kind --
I was the grunt worker left to scrape the old gaskets off carefully - it took some time, but it got done. Plan on this being a giant PIA , but worth it.

[520eek]

Very good ..... I went ahead and splurged and just ordered the rings. Seems like a good idea while I am right there. After all, when its back together and running it's intended purpose I have for it is to push a side hack around!

[canuckxxx]

So I will be replacing the head gasket soon...my question is"can it be done with out using ring compressor?" Can you you be crafty enough and pull cylinders off with pistons still in them or is it to much of a pain in the arse? The bike is coming up on 30K and runs fine..no smoking and decent poer. Was just planning on doing gasket set only and seal it back up. I would prefer to wait for a few years before I do any real top end work....

If the bike only has 30k and runs good why not just ride it?

Brian

[520eek]

Brian...

I did ride it for a bit. Then put sidecar on and rode a bit more...then head gasket started to leak. Since I am going to modify frame and alter a few things, this is the time to do so while its still easy enough done. I have found that getting sidecar aligned up is not as easy as I thought...so the next time its on and on correctly I would like to leave it that way for awhile. I am spoiled that I have a lift for maintenance and now I hate working on the ground ( if I can avoid it ). So while sidecar is off and I can use the lift....Its gonna get done. As far as the rings go....pretty sure its gonna be okay by doing them, can't hurt and its right in my hands at that point!

[canuckxxx]

Brian...

I did ride it for a bit. Then put sidecar on and rode a bit more...then head gasket started to leak. Since I am going to modify frame and alter a few things, this is the time to do so while its still easy enough done. I have found that getting sidecar aligned up is not as easy as I thought...so the next time its on and on correctly I would like to leave it that way for awhile. I am spoiled that I have a lift for maintenance and now I hate working on the ground ( if I can avoid it ). So while sidecar is off and I can use the lift....Its gonna get done. As far as the rings go....pretty sure its gonna be okay by doing them, can't hurt and its right in my hands at that point!

Well that sounds like an interesting project. Can't imagine what it would be like to drive/ride a sidecar rig.

Anyways, to answer your original question: I put new rings in my '77 GS750B a few years ago. I made 4 ring compressors using hose clamps and 3/4" wide steel banding (the kind they use strapping loads). Then, when everything was ready to put the barrels on, I rotated the crank until all the pistons were sitting at the same level. I then support them with pieces of 1 x 2 under the piston skirts. Put the ring compressors on and tightened them down and them backed them off enough that they would slide on the piston. The barrel then slid down over all four pistons at once. Just have to make sure everything is lined up and square.




Good luck.
Brian

[520eek]

Brian..

Thanks for the pics! Looks simple enough! I shall post some pics along the way as frame and sidecar project are under way... I guess I should start a new post at that time...

[canuckxxx]

When you do it you can gently set the cylinders on top of the pistons and take a close look with a light to make sure the ring compressors are right up into the bevel on the bottom of the cylinder and that no rings have sprung out. When all that is looking good a moderate, even push down should be all that is needed. Any more than that and you need to take another look.

Also, don't do something dumb like I did and forget to put the base gasket on.LOL