Standard Piston Rings? 447-11610-00

[Hench]

Hello all, happy Memorial Day. Hopefully y'all are getting some riding in.

I'm rebuilding a 1978SE engine. I bought 2 standard sets of piston rings, (447-11610-00 STD). There are the 3 oil rings, which I'm able to identify. The other two are marked R and RN. I read somewhere that R is supposed to be on top, and RN in the middle. However, they don't fit in that configuration, but they fit in reverse order, RN being the top, and R being the middle. Do I have this correct? Did I even purchase the correct rings? From what I can tell, the bores haven't been resized. (75.963)

Also, the original top ring was suuuuuper tight and damn near impossible to get off. Am I screwing up by removing them? If I am to remove them, does anyone have a technique to remove them? I got one off piston 1, but the one on piston 2 is being troublesome.

This is my first-time rebuilding anything so I'm still learning. I'm using a Haynes manual and notes from you guys to help me get through this. Thank you, Gentlemen.

 

[AUTOMAN]

Second should be moly filled(blackish)
Top is usually chrome flashed OD.

from the web:
Fits the 447 pistons. Will not fit the 256 pistons.

• 1.2mm thick top
• 1.5mm thick center
• 2.8mm thick bottom

Installation Instructions-
Chrome ring on top.
Black ring in the middle.
3 piece oil ring on the bottom.

 

[WideAWAKE]

Is there a reason you are replacing the rings?

 

[Hench]

Is there a reason you are replacing the rings?

Yes, I bought the engine from Ebay and the description stated it had low compression. I wanted to replace the piston rings to eliminate any potential causes.

 

[Hench]

Second should be moly filled(blackish)
Top is usually chrome flashed OD.

from the web:
Fits the 447 pistons. Will not fit the 256 pistons.

• 1.2mm thick top
• 1.5mm thick center
• 2.8mm thick bottom

Installation Instructions-
Chrome ring on top.
Black ring in the middle.
3 piece oil ring on the bottom.

Thank you, you're the man. Would you happen to have a link to those 256 pistons? And how did you find the piston model? (256)
I keep seeing 447 and 533. Thank you.

 

[AUTOMAN]

Thank you, you're the man. Would you happen to have a link to those 256 pistons? And how did you find the piston model? (256)
I keep seeing 447 and 533. Thank you.

Check this site for better info!

2 mins of time invested turns up this
They changed the top ring on the TX650A, after engine #010152. The change was from a 1.5 mm thick ring to a 1.2 mm ring.

 

[Its been a long time]

Here's the bulletin from Yamaha regarding piston rings -

 

[WideAWAKE]

An old motor, with tight rings, quite possibly just needed a wake up.

Did you test the compression??

Also, quite possibly needing a lot more work than rings.

What do the barrels look like? How do they measure. How do the current rings measure?

How do the pistons measure.

How did you end up at the conclusion you only needed rings??

How are the valves??? They can also leave you with low compression.

Can’t fix low compression if you aren’t fixing what is causing it.

 

[Hench]

An old motor, with tight rings, quite possibly just needed a wake up.

Also, quite possibly needing a lot more work than rings.

What do the barrels look like? How do they measure. How do the current rings measure?

How do the pistons measure.

How did you end up at the conclusion you only needed rings??

How are the valves??? They can also leave you with low compression.

I need to take some calipers to the items you're asking about, but I don't have them where I'm currently at.

All the rings came off with ease, minus the top rings on both pistons.

By barrels I assume you're talking about the cylinders. Again, I need to measure these as well as everything else.

I haven't come to any conclusions. I'm taking preemptive measures to eliminate possible failures. New rings, new seals, new gears (I don't think I need any. they all seem fine with no damage.)

I haven't looked at the valves yet. I'm rebuilding in accordance with the book. I'm currently on pistons, it looks like the next step is valves.

Again, I'm new to this. I'm not a mechanic. I'm a guy that bought a '78 to learn how to work on bikes.

 

[Hench]

Here's the bulletin from Yamaha regarding piston rings -

View attachment 327194

Thank you! This was very helpful!

 

[Jim]

https://www.xs650.com/threads/xs650-top-end-buildup.52041/

 

[Hench]

https://www.xs650.com/threads/xs650-top-end-buildup.52041/

Thank you sir! Very helpful!

 

[5twins]

A quick and dirty test for whether or not the cylinders and piston are too worn is to stick the clean piston (rings removed) back in the bore then see how big of a feeler gauge you can jam in there between it and the cylinder wall. The "new" clearance spec is about .002" and the wear limit is just under .004", so if you can fit a feeler gauge bigger than .004" in there, it's worn too much.

 

[AUTOMAN]

A quick and dirty test for whether or not the cylinders and piston are too worn is to stick the clean piston (rings removed) back in the bore then see how big of a feeler gauge you can jam in there between it and the cylinder wall. The "new" clearance spec is about .002" and the wear limit is just under .004", so if you can fit a feeler gauge bigger than .004" in there, it's worn too much.

Jam it where?
Down the throat or up the ass?

This guy has no experience so be specific.
This guy has no proper tools to measure.
Hard to find .0018" to .0025" feeler gauges in .0001" increments.

Hench, get the correct micrometer and telescopic bore gauge.
Get good at measuring with them with confidence.

cliff