Weird octagon shaped ring in top end kit

I keep getting this extra weird shaped ring in top end kits. I’m not sure what it is for? I’m thinking it helps push out the bottom ring because it fits perfect on the piston.(edited)

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Re: Weird octagon shaped ring in top end kit

yea it’s a helper ring for the bottom, v common on Japanese pistons for w/e reason

Re: Weird octagon shaped ring in top end kit

> iskra chornia Wrote:

> -------------------------------------------------------

> yea it’s a helper ring for the bottom, v common on Japanese pistons for

> w/e reason

Would you trust it?

Re: Weird octagon shaped ring in top end kit

> iskra chornia Wrote:

> -------------------------------------------------------

> yea it’s a helper ring for the bottom, v common on Japanese pistons for

> w/e reason

Yes. Use it. Install first on bottom grove then ring.

Re: Weird octagon shaped ring in top end kit

♣Slew Foot♣ /

Some p istons were made for them oileer rings bativii and hobbits they spread oil onto the ring evenly.

Re: Weird octagon shaped ring in top end kit

It's a ring expander . It helps keep the piston centered and a bit more pressure , ring to cylinder wall .

Re: Weird octagon shaped ring in top end kit

you don't need it. but it doesnt hurt and probably provides some negligible minor benefit.

Re: Weird octagon shaped ring in top end kit

no groms no blasters /

> Born to be WillD Wrote:

> -------------------------------------------------------

> you don't need it. but it doesnt hurt and probably provides some

> negligible minor benefit.

it me

Re: Weird octagon shaped ring in top end kit

> Born to be WillD Wrote:

> -------------------------------------------------------

> you don't need it. but it doesnt hurt and probably provides some

> negligible minor benefit.

I've run with and without an expander .

Not much difference , except for the hole shot to leave you on your butt and the 30 MPH more top end . ;)

Seriously , you can't tell a difference in performance .

MAYBE in longevity , but ???

Re: Weird octagon shaped ring in top end kit

> P D Wrote:

> -------------------------------------------------------

> > Born to be WillD Wrote:

>

> > -------------------------------------------------------

>

> > you don't need it. but it doesnt hurt and probably provides some

>

> > negligible minor benefit.

>

> I've run with and without an expander .

>

> Not much difference , except for the hole shot to leave you on your butt

> and the 30 MPH more top end . ;)

>

> Seriously , you can't tell a difference in performance .

>

> MAYBE in longevity , but ???

Well I would presume with no expander ring there is less frictions becuase the ring isn’t push against the cylinder wall with as much force. Probably good for like 800 rpm gain.

So yea I think the expander ring helps with longevity and just tricks the engine into thinking the rings are still good.

Re: Weird octagon shaped ring in top end kit

This from WIKI :

"Rings are also sprung to increase the contact force and to maintain a close seal. The spring force is provided by either the stiffness of the ring itself or by a separate spring behind the seal ring."

https://en.wikipedia.org/wiki/Piston_ring

Some ring sets have the top and lower rings made of what seems to be different material . I'm thinking that a lesser material used for the lower ring might not hold it's spring tension as well as the higher quality upper ring . So , the need for an expander ring .

I've also seen lower rings that are not as deep as upper rings to better accommodate that expander ring .

Re: Weird octagon shaped ring in top end kit

i c u steve rosen :D

Re: Weird octagon shaped ring in top end kit

Anonymous User /
scootertrash

Yeah or the ring with the wider gap is the lower ring.

Re: Weird octagon shaped ring in top end kit

♣Slew Foot♣ /

Lessens the backslap or rocking in a tapered cylinder...

Re: Weird octagon shaped ring in top end kit

I end up not using it, I installed it and it would not sit correctly. It was an old kit, been sitting on the self for like two years, piston was rusty and stained the cylinder too.

I still think chine makes great cylinders for beginners. For $40 bucks I can bore out my Yamaha jog use it for 400miles and pay only 10¢ per smile.

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