Where is my oil going?

[Ccitis]

No smoke... no leaks... no obvious place it is going. Running Lucas 20-50. Everytime I go for a ride lets say around 300kms, there is no oil in the sight glass when I get home. Bike on the center stand. Where is the oil going? I don't get it.

[bikerphil]

Valve seals will leak oil past them and can burn with none or very little visible smoke. If you are running synthetic, that smokes even less. I have this problem with my 79sf, only my friends riding behind me can smell it.

[Tropic-al]

So you have burned all that oil in a couple hundred mile ride ?? Does it take longer to fill back up at least some ??
If not, how much are you adding to get to the level mark ??

[Ccitis]

say 250ml to fill. Conventional oil only. It seems very odd to me. I would think valve seals would not burn that much oil....

[Radioguylogs]

The noticeable symptom of valve seals leaking:

After the bike has sat unused for a period of time (a few weeks),... when you start it, it will make a lot of smoke. The smoke diminishes after the oil burns off the exhaust ports in a few minutes.

.

[bikerphil]

If you're running steadily above say 4500 rpm, the consumption will be greater. Worn rings, same deal. Check your motor for blow by.

My friends XJ11 had the same issue. We did new rings, ball hone the cylinders and new valve seals, oil consumption problem gone.

[DEEBS11]

Yes, the top end needs both rings and seals and it will last another 45 years. These are just normal wear items. However, don't use Chinese crap parts when replacing.