Yamaha 9.9 4T oil consumption

[panasonic]

Sir you need them cylinders roughed up (honed) so the new rings will wear in. The cylinders are to smooth now and the rings won't seal properly.

So two choices:

live with it

or take it apart yet again and have the cylinders honed.

[pakostane]

If I would hone cylinder now I need to buy new rings and all gasket. If I left engine now without hone will consumption decrease for some time?

[pstephens46]

Is it also true that honing helps to trap a small amount of oil to help lube the rings?

[99yam40]

new rings are not smooth and neither should be the cylinder walls so they will wear in together. Yes a rough surface would hold more oil than a smooth surface when rubbing together.

the rings may wear in eventually, but I think it would be way on down the road rubbing on a slick/smooth surface.

think about sharpening a knife, you use a rough stone to get the main shape to start out with, and then a finer one to finish it.
as the rings and cylinder walls wear they get smoother and finally get that fine seal together

[TownsendsFJR1300]

What was the ring end gaps of the old rings vs the new rings?

Did you check valve/ valve guide wear while doing the seals?

Any excess carbon / oil build up when you had the engine apart?


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[99yam40]

Scott post 98 has the ring info you asked about

[TownsendsFJR1300]

Scott post 98 has the ring info you asked about

Thanks, well, they were worn...

There has to be some evidence of excess oil somewhere.

As I'm too lazy to look thru 100 posts, was a leak down test ever done?



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[99yam40]

nope, not even a compression.
not even sure they used proper ring gap measuring as they said it was .6mm on all rings to start out with

[TownsendsFJR1300]

nope, not even a compression.
not even sure they used proper ring gap measuring as they said it was .6mm on all rings to start out with

Where's Rodbolt?

Someone needs a verbal spanking by a pro...

[pstephens46]

Geez. 114 posts for a 9.9?

[dray0151]

Geez. 114 posts for a 9.9?

Yours was 115 and now 116 is that a record???????

[pstephens46]

Actually, the record appears to be 208...

[panasonic]

If I would hone cylinder now I need to buy new rings and all gasket. If I left engine now without hone will consumption decrease for some time?

You already have the new rings. We are talking about honing the cylinder's to take the glaze off...(rough them up)

We are not talking about boring out the cylinder's.. They are two very different things.

You will need a new head gasket, that's it.

[panasonic]

Geez. 114 posts for a 9.9?

Now don't be talking down on the little 9.9 HP....she will get you there, it will be awhile, but she will get you there...lol

[dray0151]

Do none of you replace bearings when you take an engine apart after they have been torqued and used?

In past racing life we would never have put crank or rod bearings back in an engine.