Piston ring taper - urgent help needed.

[Mad Ratter]

Hi all, just fitting new piston rings to new pistons on my 1978 GS550, in the manual its says that the 2nd ring is tapered slightly so the ring goes on a certain way, but I have studied and studied the ring profile, but it appears to be square and not tapered and in fear on fitting it the wrong way up, does anyone know if the "new" rings are no longer tapered, or am I missing something?

Cheers.

[7981GS]

Look for any kind of a mark right at the ring gap.
It could be a dot, a triangle, etc.
That side goes up towards the valves.

Eric

[Steve]

Also, don't forget to check the end gap.

Not sure if that procedure is covered in the manual, but it is in all the basic auto mechanics classes I have seen.

If you don't know how to do it, please ask.

.

[Mad Ratter]

Thanks guys, there was a little "T" at the ring gap, couldn't see it until I put a friends glasses on and a flashlight!!!
New rings installed to new pistons
I have a diagram to set the ring gap positions.

[7981GS]

Steve was reminding you to check the ring end gap also.
Be sure to do this as you don't want them too tight in the bore.

Eric

[Steve]

I have a diagram to set the ring gap positions.

Yes, position is important, but probably not quite as important as SIZE.

You need to check the SIZE of the end gap to make sure it's not going to bind in the cylinder or be too large to provide proper sealing.

You are making it obvious that you don't really know what you are doing, it's good that you are at least asking questions.

.

[Mad Ratter]

Yep! first time doing this, the rings are brand new so surely the ring gap would be correct? If not, what the hell do I do then?

Thanks for replies

[hampshirehog]

Yep! first time doing this, the rings are brand new so surely the ring gap would be correct?...

If they are the right rings in the right bores. If the gap is wrong you'll need to change something.

[Steve]

Yep! first time doing this, the rings are brand new so surely the ring gap would be correct? If not, what the hell do I do then?

Thanks for replies

I don't know about the way rings are being fitted today, the last time I had to change any rings was MANY years ago, and it was in a car. Those rings were intentioinally ever so slightly long, and had to be filed to fit.

The process requires placing a ring in the bore so it is perfectly perpendicular. The easiest way is to push it into place with a piston, but that requires removing the piston from the rod. You then measure the end gap and compare it to specifications, adjust if necessary. Nothing you can do to close up the gap, but you can certainly enlarge it if necessary.

Sounds like a bit of work, but personally, I think it's much easier now, while the engine is already apart, rather than having to take the engine apart again to replace parts that were damaged because the gap was incorrect.

.

[barnbiketom]

Yes. push the ring into the bore a couple inches by itself and use a piston to make sure it is straight in. not cocked. then measure the end gap with feeler gage or whatever. if it is too tight, remove the ring and place in a vise gently with wood pieces and file one end.. keep checking till it is within spec.
If it is too large (which I doubt) theres nothing you can do but check to see if the rings are correct for the application, bore size, etc. or just let it go. but I never had any that had to large a gap for some reason.

[Mad Ratter]

Ok, I have a manual that describes the procedure, thanks guys

[OLDENUFF]

If you have to file the rings, place the file in the vise, not the ring.

[5150/gs]

the way i have done it,rebuilt 2 top ends this summer,I used a bench grinder with a very thin disk,but have a good eye to keep it straight,and do very little at a time,don't want to go too far.Takes time and patience,I honda kr70,1974 that is,and a yamaha blaster,much less rings in that one.good luck and take your time!!!little at a time there

[kirkn]

+1 on putting the ring in wood blocks in the vise. I was never crazy about the idea of moving the ring back and forth on the file, but that'd work too.

There should be a spec for exactly how far down into the bore you push the ring for the check, too. The bore can have a taper, and too far down or too far up can give an incorrect ring gap reading. Two inches sounds like too much. The times I've done it, it was ~1" down.

Just my two cents.

[1948man]

I never knew the bore would have a taper other than the chamfer at the end.