Head Questions

[uudfourty]

Hey fellas:

1981 GS550L

Pulled head and cylinder yesterday. Started cleanup today.
I've got a couple of questions.

First, what is this?

It fell out of the head when I flipped it over to start cleaning the chamber. There are two of them. Looks to be a bushing of some sort.
It might have just been riding around in the fins from a previous job. If it doesn't look familiar, then forget about it.

Second, how serious is this pitting?

It's like that across the board.

The only thing I've used to clean this are the car wash, some degreaser, red rags and the tab off of a tallboy, so It wasn't me. There's pretty strong evidence of the PO's presence in the head and cylinder area.
That little rectangular o-ring that sits atop the cylinder was in two separate pieces with silicone in the gaps. Eyes--> rolled.

Thanks for your time, fellas.

Edit: Any tips for pulling out exhaust gaskets? Mine seem to be rather resilient.

 

[tone]

The first thing looks like a dowel which sits between the head & barrels to correctly locate them

The pitting is not too bad & shouldnt cause a problem with running imo, your valves do need lapping in though

 

[Calvin Blackmore]

looks like dowle pin
http://www.bikebandit.com/suzuki-motorcycle-gs550lx-1981/o/m6085

could alos be pins from http://www.bikebandit.com/assets/schematics/Suzuki/SU0094_005.gif


lok like fat pins that act as a pin and a pass through shroud of sorts for a head bolthttp://www.bikebandit.com/suzuki-motorcycle-gs550lx-1981/o/m6085

 

[Nessism]

Do you have aftermarket coils? Those cylinder pieces look similar to a piece that spaces the coils away from the frame. I don't think they are dowel pins that hold the head/cylinder in alignment since they look too thick.

The pitting looks a little questionable - most likley corrosion related. It might be advised to have the head skimmed to clean up the sealing surface. Better safe than sorry.

Removing those exhaust gaskets usually can be accomplished by prying with a screwdriver. If you have a strong hook tool that might be better still.

Good luck and don't forget to pull those valves and so you can check for wear, lap, and replace valve stem seals.

 

[tone]

After looking again i think nessism may be right, they do look to thick for dowels & there is no chamfer

 

[Calvin Blackmore]

Did anyone look at the parts fiche?
they are pins I say, Pins and let all the world be damned!

 

[uudfourty]

Yeah, I've got dyna coils. I was thinking that the mystery cylinders looked somewhat familiar, but I wanted a second opinion.
The mystery cylinders fell off of the top of the head when I flipped it the first time, so that makes the most sense.

I'm going to lap the valves and put in some new seals, because I know for sure that one of them was leaking a bit.
( http://www.z1enterprises.com/detail.aspx?ID=1583 , right? )

For lapping-- lemme get this straight:

I disassemble the valve down to where it's just the valve itself.

Then I clean up the valve and the seat as well as I can.

Then I take some lapping compound and rub around the valve where it
meets the seat.

Then I spin it back and forth for a while with a suction cup on a stick, occasionally pulling it out a ways and smacking it back down. Doing this for about a minute.

Then I clean the compound off, reassemble, and carry on.

Right?

Also, this is a 1981 GS550 that I paid $550 for about 5 years ago.
I've since put around a $600 into it... ugh... I love working on it, I just can't afford it.

I'm a broke white boy, and I'm not trying to turn it into a high performance 550-- I'm just trying to take care of it.
So anything that starts with "take it to a shop and have them..." is pretty much out of the question.

 

[tone]

Then I take some lapping compound and rub around the valve where it
meets the seat.

Then I spin it back and forth for a while with a suction cup on a stick, occasionally pulling it out a ways and smacking it back down. Doing this for about a minute.

Err no keep at it untill you have an unbroken grey line all the way round the seat & valve If they are really badly pitted you may not quite manage this but that is what you are aiming for in the ideal world

& if you can do a valve in a minute ive got 48 here for you to do :lol:

 

[uudfourty]

Okay, cool. That's what I needed to know.
Otherwise, my procedure is more or less correct?

 

[tone]

yes its correct, just dont go too heavy on the grinding compound & remember to wash out ALL traces before you put it back together

 

[uudfourty]

10-4. Much thanks.

I'm sure I'll be here again looking for advice when it comes time to put the cylinders back on.

 

[Nessism]

Lapping should not be done to try to repair a valve sealing issue, it's more to allow you to see what the sealing contact area looks like and maybe clean off a small amount of contamination.

Put the lapping paste on the valve and twist away for a short while. Use the fine paste. After the paste grit dissapeates, pull the valve out and look at the contact area - it should be uniform all the way around both the valve and seat. You don't want to contact area to be too wide - the service manual has a spec. If there are contact surface issues take the head and valves to a motorcycle machine shop and have them addressed properly. Again, lapping is only to check the contact pattern, not to fix a poor seal.

Hope this helps and good luck.

 

[gearhead13]

Just a tip:
The way I lapped valves is by putting in the valve and turning them with a hand drill. I don't tighten the chuck more than necessary to avoid marring the stem. On my 16v head the drill chuck wouldnt fit in to hook up to the valve stem, so I made an extension with a piece of fuel tubing. It sure is faster and easier then the suction cup and works a lot better as well.

 

[Calvin Blackmore]

so no one is going to bother looking at the fiche?

 

[uudfourty]

Hell no. Clicking links someone else went to the trouble of posting is way overrated.


I wasn't having a sealing issue, I was just going to do it as a matter of course.
The way I knew one of my valves wasn't sealing was when, after a month of sitting, I pulled the valve cover, there wasn't any oil in one of the wells by the valve shim bucket. The rest had a uniform amount.

There had been oil standing there at one time, as evidenced by the residue. I figure that it's just a slow leaking oil seal.

 

[Calvin Blackmore]

Hell no. Clicking links someone else went to the trouble of posting is way overrated.


I wasn't having a sealing issue, I was just going to do it as a matter of course.
The way I knew one of my valves wasn't sealing was when, after a month of sitting, I pulled the valve cover, there wasn't any oil in one of the wells by the valve shim bucket. The rest had a uniform amount.

There had been oil standing there at one time, as evidenced by the residue. I figure that it's just a slow leaking oil seal.

OMG hahah
too funny thats is terrrific.

 

[Big T]

You don't want to contact area to be too wide - the service manual has a spec. If there are contact surface issues take the head and valves to a motorcycle machine shop and have them addressed properly.
Hope this helps and good luck.

And that spec is generally only a few millimeters. If your lap contact area is too wide, you have to start over by cutting a new seat.

 

[Steve]

I kinda like the method I used to lap the valves on my son's 850.

I took one of the allen-head bolts that I was replacing, found some rubber tubing that would slide over the head snugly, then chucked that in my battery-powered drill. I supported the head on the pull-out section of my table saw so I could reach both sides, then slid the valve into place and lifted it just a bit with my finger. Pressing the rubber hose on the face of the valve has just enough friction to spin it. I then slid the valve into place. By the time you push hard enough to spin the valve, you are pushing the valve too hard into the head, so you have to apply a little lifting pressure on the stem. Works real nice, takes longer to find the rubber hose for the friction drive than it does to spin eight valves.

By the way, I think the spec for the contact area is only ONE millimeter, not "a few millimeters". ONE millimeter is not very big.

.

 

[Suzuki_Don]

I kinda like the method I used to lap the valves on my son's 850.

I took one of the allen-head bolts that I was replacing, found some rubber tubing that would slide over the head snugly, then chucked that in my battery-powered drill. I supported the head on the pull-out section of my table saw so I could reach both sides, then slid the valve into place and lifted it just a bit with my finger. Pressing the rubber hose on the face of the valve has just enough friction to spin it. I then slid the valve into place. By the time you push hard enough to spin the valve, you are pushing the valve too hard into the head, so you have to apply a little lifting pressure on the stem. Works real nice, takes longer to find the rubber hose for the friction drive than it does to spin eight valves.

By the way, I think the spec for the contact area is only ONE millimeter, not "a few millimeters". ONE millimeter is not very big.

.

STEVE. Pics.

 

[doctorgonzo]

About to FINALLY start mine as well (rebuild). I parked it 3 weeks ago and a couple days ago started tearing it down. I will be back with MANY questions. My main curent concern is that the machine shop took too much off my "new" junkyard head to get it true.