81 GS550T Full Rebuild...In Ohio

[Flyboy]

Ahhhh, that makes more sense Scott, service limit is 0.10 - 0.30 and you are at 0.20 to 0.25, puts you nicely in the middle.
As I read it, the spec at 0.07.
Carry on................

 

[loud et]

I was thinking back to when I ahd my engine apart and I did my valves and did use a wire wheel, but remembering now I did a little something extra that really helped.
I did a couple wraps of blue painters tape on the shaft end of the valve and lightly chucked it into my cordless drill. I held a peice of 220 grit and ran the drill and valve across the paper. Its easy to use your hand to confor the paper to the curves.It really gave it a good clean.
The main focus was originally the concave bottom of the valve, it REALLY helps the suction cup to stick when lapping, but seeing how good it worked I ran it up over the top too where the build up was.

 

[D-Mac]

As usual, lots of good advice on here.

To clean the valves, I prefer to take them in hand and put them to the wire wheel - turning slowly. I don't see anything wrong with using the drill, as long as you wrap the stems well. I learned cleaning as a 4-stage process: clean the margin, clean the area approaching the stem (although as others have said, do not let the wire touch the stem above where you have build-up), clean the sides, than then clean the face (bottom, where you attach the suction cup to lap them). Basically, just feel free to change your angle of attack as needed. Be careful that you don't have a valve go flying off on you! Also be VERY careful not to drop a valve.

I agree with the advice about lapping-in the valves. The service manual advises not to do it because of some magical Suzuki coating on the valves, but lapping won't take much off, and you won't need to wait 10,000 miles to get the benefits of an efficient engine that doesn't use oil, if you lap them now. Lapping will also clean up pitting on the valve seats, which seems really common in engines of this age.

If possible, I suggest you deglaze the cylinder, and definitely do it if you are replacing the piston rings. Ideally, you should check piston diameter (at the skirt), bore diameter (top/middle/bottom on x and y), ring end gap and side gap, and then calculate piston-cylinder wall clearance and make sure everything is in spec. That said, if you still have lots of cross-hatching on the cylinder walls, I bet you're in very good shape. I've checked four 550 engines ranging from 10,000-30,000 miles during my rebuild, and all were well within spec.

 

[cowboyup3371]

Thanks guys. Your advice is pretty timely as I started on cleaning up the valves tonight. I will have to buy a new wire brush for the drill but used the roloc style one I bought earlier this year.

What started like this on the intake valves:

Ended up like this after some time with the drill. I'm sure I have more to do before I even lap them. It's good to hear I can do the top of the valves as I'm a little nervous about messing them up.

Here is one of the exhaust valves before

and after

Then, I started to get a little lost on where I wanted to go since I really need parts before I can do much more with the engine. Yes, I'll go out to the base this weekend to dip covers in the wash tank but still.

So I played Mr Destructo with the lower steering bearing leaving this on the end of the stem near the lower triple tree. Is this still part of the bearing or is it a part of the stem? If it's a part of the bearing, how do I get it off?

After that, I grabbed a few things and went back inside.

First I repainted the kill switch thanks to Good Times. I think it will be okay though so we'll see when I get it all back together.

Then I tore into the clocks finding a few interesting items...

It was kinda neat to see the dead and decayed spider remains inside of them but yea, I don't want to see them again. Broke out the vacuum and away they went.

So, now off to go find Pete's and Rustybronco's thread about removing the odometer knob. I tried pulling on it but no luck. I'll also take some model cement to the rubber ring around the other clock casing since that's coming off.

 

[D-Mac]

Valves are looking better. There is still a little carbon you can get off (I think I have a few pics of what mine looked like before/after in my build thread). The look though.

As for the steering stem, you are making good progress, but you're not done yet. What you have left is the old inner bearing race, which must be removed so you can put on a new bearing. By far the best way to do this is to clamp the whole stem in a vice a few inches above the race (where it is tapered - somewhere in the middle part since it doesn't matter if it gets a little marred because the new bearing will easily go right over it).

After it's clamped, heat the race with a propane torch. Get it nice and hot. The race will expand a little, which can make all the difference in getting it off (especially if a little corrosion has formed between the race and the stem).

Immediately after heating, take a large drift/punch and and firmly hammer the race up off the stem (I also have some pics of what it looks like off in my thread). It's pretty easy because the race protrudes. I remember that it took a couple of cycles of heating and pounding to work mine off, and the race even chipped a little during the process. Work around it a little at a time so that it comes off evenly. Just be careful that your drift doesn't slip off and gouge the area immediately above the race. That part needs to stay smooth so the new race can "slide" on.

Installation: When you get a new set of bearings (I used allballs bearings) make sure you don't forget the washer under that lower bearing (you'll see it when you drive off that race). Installing a new lower bearing is easiest if you chill the lower stem in a freezer first (once you pack the bearing with stiff "green" high-impact grease first). Then use a pvc pipe that fits just over the stem but touches the new race close to the inside race to drive it down evenly over the stem. Sounds harder than it is.

 

[cowboyup3371]

Thanks DMac. I'll work a little more on them. When you did the tops of your valves, did you have to be careful about going too far or is that easy to do?

 

[Nessism]

The dome where your valves live is the top of the squish area. The roof, if you will. Of that speaking I was. (in my best Yoda voice.)

Nope, sorry. The "squish area" is around the very outside of the combustion chamber, as Steve said, where the piston and head almost touch.

Scott, when you lap the valves don't go to hard on them. The only thing lapping does is clean the seats. Your engine looks really clean inside. When you are done it will be like new again.

 

[Guest]

Stem bearing.
Skip to 4 minutes
video


To the best of my knowledge, Squish can be thought of any area where the piston is within 0.060 or less to the cylinder head. Its an area where gases are expelled at high velocity "squished" and that movement of charge causes turbulence. This helps in mixing fuel and air with the ignition source as well as assisting propagation of flame fronts for a better and more complete burn. Like fanning the flame.
On flat top its obvious where the squish bands are because they are any flat area between the head and piston and usually around the outside.

With the dome pistons like yours, I don't know Could be anywhere

 

[koolaid_kid]

While technically we agree, then name the area I am discussing. Besides, it is not really an area, it is a volume if you want to get technical.

 

[Dogma]

Stem bearing.
Skip to 4 minutes
video

+1 to the Dremel and cold chisel. Skip any kind of heating. Here's a relevant post from my 1000G's thread.

I didn't mention it in that post, but putting the new bearing on is just a matter of driving it on with a hammer and some kind of punch that's longer than the stem. Move around the bearing to make sure it goes on evenly. A piece of pipe that slips over the stem is ideal, though. I used the old, split bearing race to protect the new bearing. New bearing, split race on top of that, then a pipe. Hammer into place. A chunk of wood directly under the stem will protect the lower triple.

 

[cowboyup3371]

Thank you Dale that will be much easier and something I can try tonight or tomorrow

 

[Shwartz]

I'm almost there:dancing:

I finally figured out my best counterweight of all.

My great counterweight idea...and it worked beautifully

Your going to give that poor girl a complex! Years from now, I can see her in therapy.

 

[cowboyup3371]

Valve Lapping Compound

Valve Lapping Compound

I'm going to pick up some valve lapping compound this weekend to try starting on the valves next week. As the service manual calls for the Prussian Blue or Red Lead, I thought I should get,

http://www.oreillyauto.com/site/c/d...1_2121&keyword=assembly+lube+&+valve+compound

and this

http://www.oreillyauto.com/site/c/d...1_2121&keyword=assembly+lube+&+valve+compound

Will I be okay? Or do I need something else?


Which one should I use first?

 

[Dogma]

I think I'd start with Blueing the parts to see where you are before you start. No point in lapping a valve that already seats well.

I have a vague memory of machinists being wary of Prussian Blue. I'd give the safety warnings a good look. If I recall correctly, the guys at our shop like Di-chem. Or maybe that was the nasty stuff. I'm sure either is safe if you take appropriate precautions.

 

[cowboyup3371]

I removed the lower race from the steering stem but not without some drama tonight sadly. Everything started off great when I locked it into my woodworkers vise and started cutting, which went off without a hitch.

I managed to get a decent notch set into it to start with

But because I haven't completely attached my vise to the owner's workbench, the whole setup fell on the ground once I started hitting on the notch. Unfortunately, my valve parts were right below it that area on the floor in their tins ; fortunately nothing busted except for the fact I can't find one keeper. I'll keep looking tomorrow but I already found a replacement just in case.

So, I pulled the stem out of the vise and laid it in my lap but couldn't get anywhere at first until I decided to start pushing it up using my chisel. I guess this will add another way of getting it off as I was able to pry enough of it up to start hitting it from the bottom. After a few minutes:

And then finally everything off. I'll have some sanding to do to clean up a couple of scratches though. I just will be glad to get a better place to be staying in so I can put in MY workbenches.

 

[Guest]

I think I'd start with Blueing the parts to see where you are before you start. No point in lapping a valve that already seats well.

I have a vague memory of machinists being wary of Prussian Blue. I'd give the safety warnings a good look. If I recall correctly, the guys at our shop like Di-chem. Or maybe that was the nasty stuff. I'm sure either is safe if you take appropriate precautions.

What about a Sharpie?

You need to find out if you have any high or low points first, So I'd say the blue first as well.
Put it on with a light coat and see where it rub's off after a turn or so.
I use a sharpie pen with the same result.
Don't go overboard while lapping or you could score the seat and valve.

To find that keeper, try a hand full of magnets on a stick

 

[duaneage]

I put a 550T back together again from scratch, here is a thread on it
http://www.thegsresources.com/_forum/showthread.php?t=82482&highlight=thebigred&page=2

An interesting project for sure. Ask me questions if you need help.

 

[koolaid_kid]

Valve lapping compound normally comes in 2 cans, coarse and fine, paired up. Please study up on this before you do it. It is a simple procedure and will help you seat the valves correctly if done properly. Beats the heck out of having a valve job done, IMHO.

 

[Nessism]

Repeating myself again...but lapping compound is only for cleaning the seats, it's not for making a new seat. You need cutting tools to do that. If you lap too hard a ridge will form on the valve face so please go easy. Oh and that general purpose valve lapping paste will work fine.

 

[wedoo2]

Following this with interest. I have a question, was wondering what a new set of valves would cost, and if that would cause a problem or just more things to buy?