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wrk24wheel

Excessive Oil blowby

7 posts in this topic

I just purchased a 2000 WR400 recently. I am a newbee to motorcycles but a gear head in general. I have noticed what I would consider an excessive amount of oil coming from the crankcase blowby tube. I know if this where my jeep, I would have to consider rebuilding the top end.

I have tried to search for this problem on this board, but have come up pretty short. Is this something that I should worry about. The compression is real tight, runs great, not burning any oil and starts on the first kick without the choke even after sitting for a week. I have noticed that the original owner did very little maintenance on the bike if any at all. The air filter fell apart when I took it out, the oil filter looked like the original one (covered in metal shavings from top to bottom).

Please let me know if I should tear this thing down or just not worry about it at all. I am sure the bike has at least a couple thousand miles on it.

Help! TIA!

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Its quite common for people to overfull the oil causing blowback from the overflow tube. Take it for a spin, shut it off and check the oil level. While sitting the oil drains from the frame back into the motor. Check it after its sat a bit, its low, add more, now overfilled and causing blowback. It takes about 1.5 quarts. Allways check it after the ride and not before.

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Hey guys,

Thanks a lot for the feedback. I feel much better now. Has anyone figured out a way to route the hose so as not to gunk up the bike. Dirt and oil make a nice cake mix.

:)

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What type of oil are you using? A thicker 20W50 (motorcycle oil) would help reduce excessive amount of oil spitting out crankcase vent, which is caused by a worn engine's increased blow-by. You could also check your cylinder and consider getting a new piston and rings...

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I am using the Motul 10-50 Synthetic (5100) oil. I know a little oil can make a big mess, but I see oil dripping off the back of the shifter, neutral switch cover, frame, and coated just under the sprocket down.

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Wrk,

Have you warmed the bike up good and then checked the oil? I think its overfilled or your countershaft seal is bad. If you clean up the oil, wrap a rag around the end of the vent tube and tape it on, go for a 10 minute ride and you will be able to identify where the oil is coming from. Also check the dipstick after the ride.

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