GS550 valve seal replacement

[Jackw]

Hi,

Just a quick question. I am going to be replacing the valve seal on my bike and I don't want to take the head off. A buddy of mine said I can put rope down in the cylinder and bring the piston up to hold the valves in place? Has anyone done this? Is this a safe alternative to using compressed air or removing the head?

Thanks

[tfb]

I haven't done it myself, but have heard of quite a few folks doing it, seems to work fine by all accounts.

The other way is to make up an adapter by breaking the porcelain out of an old spark plug, and making it into an adapter to take a compressed air line. Then with the piston at BDC, put 100psi into the cylinder. With that kind of pressure, there's no way a valve is going to drop while you change the seals.

All the best.

[spchips]

My opinion only, but there is a good chance you will make at least a little mess (metal and dirt.) there is a lot of plumbing in the head. Just better to take it off.

Also, 1 more thing - how are you going to compress the valve springs? Is there a tool that fits on these bikes without removing the head??

http://www.thegsresources.com/_forum/showthread.php?t=105566&highlight=valve+compressor

[hampshirehog]

It can be done either way - rope or compressed air (never tried the latter but heard of its successful use). There is a chance of bending / snapping things though so I now always remove the head. That way I can check the valve seating and clean everything up at the same time.

Wally

[p_s]

The other way is to make up an adapter by breaking the porcelain out of an old spark plug, and making it into an adapter to take a compressed air line.

Have you done this? I tried to do this once and couldn't get out the porcelain inside the outer metal ring. Then I bought an adapter for under $10.

[tkent02]

I tried to do this once and couldn't get out the porcelain inside the outer metal ring.

I tried too, same result.

[tfb]

Have you done this?

I have done this, twice in fact. It's a pig of a job, I must admit. I began by breaking off as much of the porcelain as I could. Then I mounted the remainder of the spark plug in a vice, and took a drill with a suitable diameter masonry bit. Then it was all over bar the shouting. :-D

[chef1366]

Take the head off and do it right.

Valve Job