Expansion Ring in OEM piston ring kit

K

Kazoo

Member

Jul 22, 2002

17

0

• Aug 20, 2002

• #1

Just bought replacement oem piston rings for my 97 220. They come with an expansion ring which the kawi guy said goes on the bottom ring groove. I didn't find any expansion ring when I took the originals off. Are these now standard? Any experiences with these?

 

C

canyncarvr

~SPONSOR~

Oct 14, 1999

4,005

0

• Aug 20, 2002

• #2

Kawi replacement rings for my 200 didn't have one. Just two rings (of different thicknesses, no less..but the ring lands were the same!).

But the service manual shows one on the bottom ring.

I realize your asking about a 220.

 

K

Kazoo

Member

Jul 22, 2002

17

0

• Aug 20, 2002

• Thread starter
• #3

Yeah, I didn't see any such ring in my manual and at first glance after removing both rings, I certainly didn't see any expansion ring. But after having another go at it this afternoon, I gently scooped a tiny slot-head screwdriver down and, sure'nuff, there was the expansion ring hidden on the bottom. Finally got the valves put back in all cleaned up, new rings, new leaner main jet, Boyesen 607s, repacked TC2, ... feels like a new machine. Crisp, clean and mean. Still funny I never heard about the expansion ring before (??)

 

W

woodsy

~SPONSOR~

Mi. Trail Riders

Jan 16, 2002

2,933

1

• Aug 20, 2002

• #4

Expansion rings are a fourstroke thing. Most applications involve the oil scraper ring located at the bottum ring slot on a 4 stroke motor.. Kawasaki probably thought it was a good idea to apply a little more pressure on the bottum ring to clean the cylinder for a "new" bath of lubricating oil/gas mixture after each cycle!!! Pretty good idea if you think about it!!!
Woodsy

 

S

shr

Uhhh...

Apr 8, 2002

113

0

• Aug 21, 2002

• #5

woodsy,

Your probable not old enough to remember the 1970's 2 strokes that used expanders under the rings....

They were always omitted when shops did new top ends on them. The expanders would get gummed up and stick in the ring groves.

Just a note from the past...., also note that the 4 stroke uses a 3 piece ring, and what you are referring to is expander that holds the two separate scraper oil ring in place.

 

C

canyncarvr

~SPONSOR~

Oct 14, 1999

4,005

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• Aug 21, 2002

• #6

Kazoo:
So..you put yours in? Or left it out?

I just looked at a couple of pistons out of my RD (a yamaha 400cc 2-stroke). I thought I'd left the expanders out of the second ring..but they ARE there. That was a few years back...so certainly isn't a new idea on a 2-stroke.

The term 'expander' in this case isn't the same as the 4-stroke oil control ring, as shr says. The 4-stroke oil control 'ring' indeed consists of two rails (thin rings) that sit on the top and bottom of a segmented 'expander' ring. It's a wide land..commonly 3/16".

 

W

woodsy

~SPONSOR~

Mi. Trail Riders

Jan 16, 2002

2,933

1

• Aug 21, 2002

• #7

HEY SHR, Thanks for correcting me on that!! You are absoulutly correct!! I think it is GREAT to be able to make a mistake and be corrected by a fellow gear head on the other side of the country. My hats off to you!!!
Woodsy