Removing Cams - Question

[jetmechmarty]

IAW the FSM, what you oil is the threads. Just a couple drops should do it.

Does the compression test fail?

[Radioguylogs]

Compression passes when measured cold., It's 150 across the board, except #3 was 10 PSI lower than the others until I retightened the head nuts. Details are in the earlier posts of this thread.

One thing that is bothering me, is that I replaced the head gasket on an XS750 twice, using the same torque wrench, and the same techniques, and everything was fine. I did use Yamaha head gaskets.

Right now my plan is to remove the head, inspect the head gasket. Replace it with an NOS Yamaha gasket. Have a second torque wrench on hand. Consensus so far is to oil the stud threads only, and not the nut flange.

[Radioguylogs]

Removed the head.

No smoking gun. Everything looked perfect, torques felt normal taking everything apart.

I had hoped to see some carbon trails on/around the head gasket so I would know for sure what the problem was. Gasket looks like new. Aluminum surfaces are squeaky clean.

I did observe the head studs look totally dry, so I must have neglected to put a little oil on them. Geez, could that be the cause of all this trouble?

[Schming]

I tightened the head bolts (nuts) and started it today.

At first, it sounded normal except #2 cylinder didn't seem to firing, because that vacuum gauge was near 0 PSI. (That plug looks very clean compared to the others.)

As I tried to adjust #2 sync to see if it was just set too low, the awful sound came back.

It went Erk-Erk-Erk-Errrrrrrrrrrrrrrrrrrrr. It is loud and sounds like something is terribly wrong.

I drained the oil and I didn't see any metal flakes, although I haven't poured out the pan to see what might have settled.

I did notice that as the most of the oil had come out, I began to see a lot of foam in the oil. In fact it seemed like the bubbles sometimes came up from the oil. I wonder if it is exhaust residue.

Therefore, I am beginning to conclude the head gasket installation is NG.

Hi Mike, JAT Do you think this particular sound may have something to do with the starter clutch ?

[Radioguylogs]

Hi Mike, JAT Do you think this particular sound may have something to do with the starter clutch ?

I'm not leaving any stones unturned, so I should think about that idea. I have done a fair amount of cranking to perform compression testing.

I'm also wondering if it is possible for a new valve seal to pop off. Seems like there would be a lot of smoke if it did. However, I didn't let it run for more than a few seconds. I'll take a peek under the shim buckets.

[bikerphil]

Just a thought, the squeal may be one or more of the cam caps not getting oil. Dry metal to metal turning could possibly make a noise you're describing.

[Radioguylogs]

Just a thought, the squeal may be one or more of the cam caps getting oil. Dry metal to metal turning could possibly make a noise you're describing.

Thank you for your suggestions. I know you have a lot of experience with this type of operation.

There are rub marks on few of the cam journal surfaces, but they were all loaded with fresh clean oil. I remember seeing the rub marks when I took it apart the first time. They are not deep scratches, just areas that look a little more shiny. Maybe I can post a picture tomorrow.

Meanwhile, tonight I removed each valve and inspected. Each valve moves smoothly, and seats nicely. Each new valve seal is sitting snugly in place. Everything look perfect in there.

[bikerphil]

Another thing that comes to mind, one time I had an intake boot leaking at the head and it was making a chirping sound, may have sounded like squeaking.