CB550K3 oil control ring problem.

[Nurse Julie]

What measurement do you want, thickness and depth?....oh, and I have very small hands. Vernier and rings ready in a mo

[Nurse Julie]

The outer rings of the oil ring are 0.45 thickness and a depth of 1.82. The part I think you are calling the spacer is 3.25 thick and a depth of 1.90

[Ashdowner]

Right. Are those new rings? What manufacture are they?

The rings I took out are 1.92mm across so we're in the same ball park whereas the rings DS have supplied are 2.24mm across which makes a difference of 0.6mm difference in the ring diameter which in this context is absolutely massive.

[Nurse Julie]

New, Riken.

[Seabeowner]

I have a set of pistons and rings (not fitted) for 0.5mm O/S from Cruzinimage as I was thinking of getting my my spare 550 block rebored as a load of cooling fins were damaged on the one on the bike. Their oil control ring is 2.26mm, .45mm thk. Reading this I've just tried the oil ring set in one of the pistons. Rings went on OK, but as I have not got a bore to try I cannot say they will go in, but  looking at it, I think they would go in ok using the taper and a bit of oil. I've always found getting the compression rings started is the most difficult bit as the piston is only just engaging with the bore
The oil rings in the standard bore at present are 1.95mm, .45thk. But as a friend has repaired a whole section of broken cooling fins I will probably stick with this and not bother with the rebore at present.

[Ashdowner]

Seabeowner  - by compressing them by hand what sort of ring gap can you get down to?

[Ashdowner]

Julie where did you get your rings from?

[Seabeowner]

With best effort, probably down to maybe 1.1mm. They show about 2.4mm gap before compressing.
Phil

[Nurse Julie]

Julie where did you get your rings from?

Not DS.

[Ashdowner]

The gap when the ring is in the bore is less than 1mm. Maybe 0.7. Anyhow everything is on it's way back from DS and they maintain the rings are right. I'm going to borrow some ring compressors and if they still won't go in then I'll put the old ones back in.

[Seabeowner]

According to my (old) 500/550 shop manual the oil rings gap should be 0.3-0.9mm std and 1.1mm at end of life. But the manual only covered up to the 550K0 I think, so may be different for later Ks.
Phil

[Ashdowner]

I have no option but to discard the new oil-control rings I got from DS and use the old ones. The new ones will not fit - period. If my bores have got cross-hatching on them does that mean they've recently been honed?

[Ashdowner]

Final comment. I've had to use the old oil control rings (although I'm not sure they're that old) with the new Riken top and 2nd rings supplied by DS. IMHO there is absolutely no way that the new Riken rings would compress down to fit the bore.