Where is the oil going?

Thanks to The ThumperTalk board I got my 99 YZ400 running smooth again, but I seem to be going through a lot of oil. In 6-8 hours over 2 days I used about a 1/2 quart of oil. It is not leaking or burning oil. Is this normal? Temperature is around 85. I am using Castrol GPS 10-40.

Thank you

Richard Rowe

Is it normal?....Anyone?


No it is not normal. It should not use that much oil between oil changes

Timo Mc

In 6-8 hours over 2 days I used about a 1/2 quart of oil. It is not leaking or burning oil. Is this normal?
What is is impossible. Oil does evaporate, but not in anything like that quantity. If it really isn't leaking, it's burning oil, plain and simple.

It takes a remarkably small amount of oil leaking or burning to accomplish this. One drop on the ground every 100 feet would cost you your half quart in 175 miles, or about 5-6 hours, on average. To burn that much, you'd need only 0.00046 cc in the combustion chamber each time it fires, so it won't necessarily leave a smoke trail everywhere, either.

I'd suspect rings, and then possibly intake valve seals, if there really are no leaks.

So I get to the track yesterday after putting 1/2 quart of oil in. Start it up let it run for a few minutes. I then had to help aa friend unload. So before I started it up again I thought I would check the oil level. Yep, it was now over full. &%$#@!. In the shop it showed 1/2 quart low. Then at the track I am over. It sat about 20 minutes after I started it. :crazy:

First of all, get a manual. secondly you can only get a good oil level reading after the bike has been warmed up properly and then turned off. you then remove the dipstick clean it and insert it into the frame. DO NOT screw it in, just le the threads rest on each other. pull it out and get your reading. Sounds to me like you need to drain about a half quart of oil out. Your bike is fine this was your mistake :crazy:

If the bike is allowed to set longer than 5 minutes, the reading you get can be lower than the actual amount of oil present because the oil may have begun to drain back to the crankcases to a significant degree. This is especially true if you use a 10w-40 oil and your oil pump has some time on it, since the clearance in the pump is what the oil leaks past to get back downstairs.

If your bike is now a half quart over, better drain the excess off, as anything more than around 2 quarts will cause excess oil to be forced back to the top end from the tank by way of the vent tube, and you'll have a smoky mess on your hands until the extra gets burned off or blown out.

Thanks Gray.

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