TOPIC:

How big a job is doing the valve stem oil seals?
I suspect mine are on the way out, they are 35 years old after all.

Big enough that it involves pulling the head.

Now, as a job, this isn't too bad. If you don't have the American emissions system in place, pulling the things like the valve cover and camshafts to get to it isn't bad at all. The issues arise when you have to get replacement gaskets when you put it back together. An OEM head gasket alone cost me $100, and that was off Ebay (they are OOP). Aftermarket gaskets are available, but use at your own peril.

Pulling the valves shouldn't be too hard, so long as you get the right tool. You'll need the valve spring compressor that looks like a large C-clamp. The ones that grab the spring from the top and "pull" it up won't work, as most of the spring is buried in the head. Just be sure to keep ALL the buckets and shims separate, and put them back where they came from. DON'T MIX AND MATCH!

I haven't got around to putting mine back together yet, but getting the camshafts back in can be a bit tricky. It involves getting both oriented correctly, and a certain number of chain links apart. Then, as they are tightened down, it has to be done evenly, because you end up fighting several different valve springs as you are doing so.

If you can afford a manual (or check the downloadable ones on the site, but I prefer a paper copy), I HIGHLY recommend doing so. This isn't a hard job, but you do have to be conscious of what you're doing. Otherwise you can put a valve though a piston, which is never fun.

Good luck, and if you have any questions, feel free to ask. I'm preparing to split the cases on mine to fix a bent rod, so as far as teardown goes, I've done it all, and recently, too.

Has anyone used compressed air to charge the cylinder and thus keep the valves in place while the seals are being replaced? I've never used this method myself but I understand it's a viable option which would alleviate the need to suffer the anguish of head-gasket issues !

Worse case scenario: a valve does drop and the head has to come off regardless.

Bent rod ? How did this happen ?

I did the seals a while ago, had the head off during a re-build, I am an average aussie and ain't got any spare dosh (money), I had an automotive spring compressor and tried to use that, because of the angle of the springs and valves and the width of the head I found I couldn't compress them enough to easily take the retainers out to free the valves, so I cut a piece of pipe and tacked it onto the compressor foot, cutting out the sides of the pipe allowed me to easily get at things, make do when you have to, worked for me

scotch wrote: Has anyone used compressed air to charge the cylinder and thus keep the valves in place while the seals are being replaced? I've never used this method myself but I understand it's a viable option which would alleviate the need to suffer the anguish of head-gasket issues !

Worse case scenario: a valve does drop and the head has to come off regardless.

Bent rod ? How did this happen ?

Biggest reason this won't work is due to head geometry. Valve adjustment on these bikes is with a shim-over-bucket system. The bucket needs something to ride in, which means that the top of the valve spring is flush with the top of the head assembly. There's no way to compress the spring to get the keepers out (and by extension, get the springs out of the way to get at the valve seals) without having access to both sides of the valve.

Now, Goldwings (the 4 cylinder models, at least) run rocker arm camshafts- only one camshaft per cylinder that runs both the intake and exhaust valves. It would be a single overhead cam, were it not for the funky boxer arrangement. In any case, most of the valve spring is exposed. A lot of guys will run a length of rope into the cylinder via the spark plug hole to keep the valve from dropping, clamp on one of the external valve spring compressors, then remove the valve spring(s) and valve seals like that, without ever having to remove the head.

As for my bent rod? Tough to say. It was the No. 3 piston, and if I had to guess, I would say the PO left it on the side stand and the middle carburetor got stuck open. Fuel filled cylinder number 3 (either because it was downhill or because it was the only one with an open valve), and the next time he tried to start it, he hydrolocked it. Whatever the reason, all it means is a long winter project for me....

scotch wrote: Has anyone used compressed air to charge the cylinder and thus keep the valves in place while the seals are being replaced? I've never used this method myself but I understand it's a viable option which would alleviate the need to suffer the anguish of head-gasket issues !

Worse case scenario: a valve does drop and the head has to come off regardless.

Back in the mid 1980's the Chrysler and dodge big block needed valve seals about every 50.000 miles. I had a spring compressor that compressed the spring against the spring valve retainer. I used to use the compression tool hose from my tester and hook it up the my air compressor and apply 100psi to the cylinder at bottom dead center, compress the spring and tap the end of the spring compressor to release the retainer keeps. If you tapped too hard the valve would pop off the seat but wouldn't drop in the cylinder because the keeps were still in the retainer.
Another method which worked for a lot of mechanics was to get the piston up to top dead center, then rotate the crank about 45 degrees and then push in about 8-12" of 3/8" nylon rope into the cylinder through the spark plug hole, then rotate the crank back up to top dead center and the rope would hold the valves up in their seats. Never had a valve drop.
There used to be tooling for compressing valves that are in pockets which use bucket shims. It required removing the camshafts and placing a mandrel in place of the camshafts then a spring compressor pushed down on the spring retainer by using the mandrel as a fulcrum. I've seen the tool but never used it.
Not having to remove the head saves time and money, but if the seals have been gone for a while then you can be guaranteed that there's a build up of carbon on the back side of the intake valve. I've seen the result of a chunk of carbon breaking off of the intake valve and getting sucked into the cylinder and jammed between the piston and head. It's not pretty. If you've got the time and the extra $100 for the head gasket, you're better to pull the head and "do it right the first time"