2021 Yamaha YZ250F Oil Consumption

michigan906
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31
Joined
3/23/2020
Location
Royal Oak, MI US
4/26/2022 7:55am
2021 Yamaha YZ250F consuming oil? I noticed on my recent oil change that the oil in my sight glass was low, the interval was about 7 hours from my last oil change, a combination of some light riding with a few race pace hours.

The oil change with filter spec is 750cc, I emptied the used oil and measured it which came out to approximately 600cc.
>I see no visual signs of oil leaking externally
>Top end has approx. 18 hours on it with OEM piston/rings/cam chain/shims/tensioner.
>Motor has a total of 60 hours on it, stock bottom end.
>Latest oil change showed no signs of metal shavings or damage and has good oil pressure when checking the oil pressure check bolt
>Some white smoke out of the exhaust during initial warm up and then disappears.

What are the possible areas of where the oil could be escaping? Valve guide seals? Piston rings? Crank case breather?
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FGR01
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10/1/2006
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AZ US
Fantasy
1334th
4/26/2022 8:33am
Valve guide seals and rings are the 2 most likely. If you can remove the intake boot and look at the backs of the intake valves leaky seals will sometimes cover the back of the affected valve with black oily buildup.
Leeham
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10/29/2018
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Rochester, WA US
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4/26/2022 11:44pm Edited Date/Time 4/26/2022 11:44pm
Valve guide seals. Brothers 19 smokes a bit on start up but isn't noticeable after running. His oil level goes down a touch. He got a new piston maybe 5 hours ago also. We replaced because we thought it was piston rings. Still smokes a touch.
Moto520
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2/4/2013
Location
Schaumburg, IL US
4/27/2022 9:34am
Are you putting 750CC with an oil and filter change? Some of that oil can stay in the cavities of the motor depending on how anal you are about how you do the oil change. ARe you getting the 750CC in completely? I have to add a little more to my measurements because the oil is so thick and doesn't completely empty from my container.

Dumb little shit like that......i would make sure you aren't missing something simple.

I don't mean to imply that you are doing anything wrong with the oil change but i've seen how some of my buddies do it and it's not as anal as i do it.

btroxler
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5/22/2017
Location
Saltillo, MS US
4/28/2022 9:29am
I agree with Moto520 as well, but the smoke upon start up is the valve seals. They are letting oil get by and sits on top of piston until you start up.

Pull the head and change the seals.

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