Cylinder Head preparation

[Guest]

I bought a complete head assembly, including camshafts, on EBay for my 650G. Its a low mileage piece and the valves are almost brand new. I plan to swap the complete head on my '81 (75,000 km/45,600 miles) before next spring-better than a valve job, I figure.

Question-Since it was removed in a shop, sat around with the cylinder head cover removed, and then was packed in paper for shipping, it has picked up a bit of grit (minimal) I can hear when cleaning, oiling and reinstalling the shim buckets. Is there a standard process for cleaning before installing?

[Nessism]

Are you going to replace the valve stem seals? I strongly recommend that you do. It's much easier to properly clean the head after it's taken apart. Number the valves and buckets so they get installed back where they came from. While you have everything apart, degrease everything using Simple Green, or your favorite flavor. If you are going to lap the valve, do this before cleaning.

Good luck.

[Flaggo60]

Are you going to replace the valve stem seals? I strongly recommend that you do. It's much easier to properly clean the head after it's taken apart. Number the valves so they get installed back where they came from. While you have everything apart, degrease everything using Simple Green, or your favorite flavor. If you are going to lap the valve, do this before cleaning.

Good luck.

Nessism, I wasn't planning on doing anything to the assembly, its in such good shape. If its a low mileage piece, shouldn't everything be OK?

[Nessism]

Nessism, I wasn't planning on doing anything to the assembly, its in such good shape. If its a low mileage piece, shouldn't everything be OK?

Why gamble?

If it were me I'd first remove any carbon in the combustion chamber and ports. Next, take everything apart, inspect, and lap the valves. As I said before, keep track of where the valves and buckets go. Next is to clean everything, and lastly, reassemble with NEW valve stem seals. The amount of work involved is not that much when you consider how far you have gone already. And speaking of that, are you replacing the rings while the head is off? Always a good idea. Needless to say, replace the base and cylinder head gaskets. Some people pulling the head leave the cylinder alone and wind up with base gasket leaks. I say, do the job right and you won't have to worry. Short cuts are long cuts when it comes to old hardware.

Good luck.

[Flaggo60]

Why gamble?

If it were me I'd first remove any carbon in the combustion chamber and ports. Next, take everything apart, inspect, and lap the valves. As I said before, keep track of where the valves and buckets go. Next is to clean everything, and lastly, reassemble with NEW valve stem seals. The amount of work involved is not that much when you consider how far you have gone already. And speaking of that, are you replacing the rings while the head is off? Always a good idea. Needless to say, replace the base and cylinder head gaskets. Some people pulling the head leave the cylinder alone and wind up with base gasket leaks. I say, do the job right and you won't have to worry. Short cuts are long cuts when it comes to old hardware.

Good luck.

Those are good points, thanks. As the work is part of the first overall renovation this machine has had, and its been so good to me up to this point, the additional work is warranted, now that I think about it.

The one thing I don't know, having never done it, is can the work be done with the engine in the frame?

[Big T]

I agree with Nessism. Even though it appears to be in good shape, those seals are over 25 years old. Replace them.

If you lap the valves, do so carefully. 2-3 mm of shiny metal is all you need for a good seal. Once you take the valves out, post up some pics to see if you need to lap the valves at all.

And yes, the entire top end of the motor can be changed out with the motor left in the frame.

Do you have a manual and a torque wrench?

[Flaggo60]

I agree with Nessism. Even though it appears to be in good shape, those seals are over 25 years old. Replace them.

If you lap the valves, do so carefully. 2-3 mm of shiny metal is all you need for a good seal. Once you take the valves out, post up some pics to see if you need to lap the valves at all.

And yes, the entire top end of the motor can be changed out with the motor left in the frame.

Do you have a manual and a torque wrench?

It's easy to forget the age of this cylinder head, it looks so new, but yes, you're right, the seals age and should be renewed. I'm glad to hear I can leave the main bulk of the motor in place. Is this the case if the rings are replaced as well?

I have both the Clymer and the factory manual as well as a torque wrench, so my winter project is starting to shape up pretty good. Thanks.

[chef1366]

Do the valve stem seals, rings and base gasket and ride another 75,000.

[Suzuki_Don]

Yes. You can do the rings and the valves with the crankcases left in the frame. While you are at it, I think it would be a good idea to replace the carbs to cylinder head "O" rings from Robert Barr and give the carbs a good soaking in the "dip" of your choice seeing as they will be off the head anyway.

[Flaggo60]

Yes. You can do the rings and the valves with the crankcases left in the frame. While you are at it, I think it would be a good idea to replace the carbs to cylinder head "O" rings from Robert Barr and give the carbs a good soaking in the "dip" of your choice seeing as they will be off the head anyway.

Don, the carbs have been dipped and the O-rings have all been done, as a matter of fact that's what started the whole reno in the first place-now it seems I can't stop!!

[Steve]

... can the work be done with the engine in the frame?

I know you are talking about a 650, but here are a couple of pictures of an 850 that might answer your question:

[Flaggo60]

I know you are talking about a 650, but here are a couple of pictures of an 850 that might answer your question:

Thanks, Steve, those are good pictures and definitely show that the work is do-able. Once I get to that point I will definitely be back to the Forum as I've never attempted anything like this before. How did you go about getting the pistons with their new rings back up into the cylinders? It looks like a minimum two person job, am I right?

[Piston720]

Hello. Hope you don't me cutting in. Grimsby Ontario. My 79 850 looks exactly in the same state as the pictures, except I have rags covering the crank opening.
I will be taking the parts for a high temp chemical dip, then start reassembly. I have yet to measure up the piston and rings per the spec sheets. Probably would be a good idea to replace.
One of the toughest parts of the clean is to remove the base gasket from the lower cylinder head, it is almost fused on.
This is the first overall on this 90000K bike, as I am the original owner.
So far it has been MOSTLY enjoyable.

[Flaggo60]

Hello. Hope you don't me cutting in. Grimsby Ontario. My 79 850 looks exactly in the same state as the pictures, except I have rags covering the crank opening.
I will be taking the parts for a high temp chemical dip, then start reassembly. I have yet to measure up the piston and rings per the spec sheets. Probably would be a good idea to replace.
One of the toughest parts of the clean is to remove the base gasket from the lower cylinder head, it is almost fused on.
This is the first overall on this 90000K bike, as I am the original owner.
So far it has been MOSTLY enjoyable.

Looking at the photos it appears that Steve has some work to do on the base gasket remnants as well. Is this the first time you've done this? Still curious as to how you go about compressing the rings to fit up into the cylinders when you lower the cylinder section down over them, it seems to be quite tight and awkward when you leave the engine in the frame....

[waterman]

I have been done this road, I have to agree with the others. Don't take shortcuts, make sure everything is spotless before reassembly.

A couple notes, I used the valve seals that came with my complete gasket kit from Vesrah. I used a OEM Suzuki head gasket, had to make my own cam tensioner gasket.

As for the piston installation, two people are great if they know what they are trying to accomplish. The service manual describes a piston holding tool which makes installation easier. Plenty of patience, a fair amount of oil, and a steady hand will get them back in. I used large hose clamps for the ring compressors, again you will need to set them just snug enough to compress rings yet still slide up and down piston.

This repair can be done in frame but I would pull engine out if I was going to do it again. It is a lot easier when you can stand up and wrench on these. This also makes it easier to replace oil pan gasket and clean motor and frame. It is not really all that more involved to get motor out, biggest trouble is weight. The manual says to remove head and all that stuff, if you have a friend, you can get it out without much hassle. I do recommend a wheeled floor jack to assist when lift out of frame. The 650 engine isn't quite as heavy as larger 850 and up motors, I lifted mine up from floor to bench.