Ring gaps moved on 1979 GS1000

[Guest]

After reassembly and a few short test firings, I checked the compression and found 1-4 at 135, 97. 107 & 128. Since I also had a base gasket leak I decided to pull it down and check it out again. The gaps on the top 2 rings had moved close together on #2 and were almost directly on top of each other on #3. The rings are within spec dimensionally. Anyone else ever had this experience? Trying to decide if I should replace the #2 & 3 ring sets or set them correctly again and see what may happen. Thanks for your consideration. Ray

[Steve]

Unless there is a pin in the piston groove and a notch in the back of the ring, what is there to keep them from turning?

On the other hand, what is there that might make them turn?

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[Guest]

Yup, they turn.

[Nessism]

While the engine is apart it’s a good idea to check the cylinder for wear, out of round and taper, as well as piston to wall clearance. On the piston itself, the ring to piston clearance should be checked as well.

If the system has wear is could be causing your rings to walk more than expected, and/or upset the ring seal. Verifying all the details is never a waste of time and may well turn up a problem…or provide you with peace of mind that everything is okay.

[tkent02]

After reassembly and a few short test firings, I checked the compression and found 1-4 at 135, 97. 107 & 128. Since I also had a base gasket leak I decided to pull it down and check it out again. The gaps on the top 2 rings had moved close together on #2 and were almost directly on top of each other on #3. The rings are within spec dimensionally. Anyone else ever had this experience? Trying to decide if I should replace the #2 & 3 ring sets or set them correctly again and see what may happen. Thanks for your consideration. Ray

Get your leaks fixed and give it a good run up your favorite local canyon to seat the rings, the compression should come up.

[hampshirehog]

The rings will move around in a spot on motor (and reasonably quickly - one of the manufacturers put together a report on it). The idea of setting the spacing on a rebuild is to minimise the chances of the rings aligning, though the law of averages suggests that they must from time to time.

As I understand it they spin because they aren't perfectly round, nor is the bore.

[Guest]

Thanks for the responses. The cylinder and pistons are within service limits and look good. I know they eventually do turn but was surprised to find them that far from the installed location so quickly. I think I'll follow Tom's advice and slap it back together and see what happens. Thanks, Ray

[doctorgonzo]

As I was installing mine with the gaps per the diagram in the manual I was thinking... "seriously... they are gonna STAY this way?"

[Steve]

I was only bringing up the idea of pinned rings because I have seen them in the past. I can't remember exactly what engines they were, but I seem to remember that they were primarily boxer engines, like VW, Porsche, Subaru, Ferarri, etc. The basic idea was to keep the gap above horizontal to minimize oil seepage.

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[Sandy]

I was only bringing up the idea of pinned rings because I have seen them in the past. I can't remember exactly what engines they were, but I seem to remember that they were primarily boxer engines, like VW, Porsche, Subaru, Ferarri, etc. The basic idea was to keep the gap above horizontal to minimize oil seepage.

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You'll find pinned rings on 2 strokes so they don't rotate and catch on the ports. It's on 4 strokes where they're not pinned they rotate, at least any I've seen.

[Steve]

Yeah, I forgot about the 2-strokes.

I guess I would have been reminded rather quickly when I get into doing the restoration on my wife's X-6 Scrambler.

[doctorgonzo]

Yeah, I forgot about the 2-strokes.

I guess I would have been reminded rather quickly when I get into doing the restoration on my wife's X-6 Scrambler.

REALLY considering a stroker for me next project. a 120 MPH bike with a hingey frame and bad brakes.. hell yes!