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Yami426

Why is oil dripping from a breather tube on my yz426

8 posts in this topic

I got this 2000 yz426 a couple weeks ago and i noticed after riding even 5 minutes a few drops would come out the breather tube that comes out of the top of the engine thru the head. Im just wondering why my bike would do this any suggestions?

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The bike's oil level is probably to high. Make sure at the next oil change you completely drain the bike and refill to proper level, which I believe is 1.6L or 1.7L with a filter change.

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I got this 2000 yz426 a couple weeks ago and i noticed after riding even 5 minutes a few drops would come out the breather tube that comes out of the top of the engine thru the head. Im just wondering why my bike would do this any suggestions?

3 things cause 426's to have blow-by.

1. Too much oil

2. Running them at a high RPM (for an extend period of time)

3. Worn rings

They all puff air out of the tube, but they shouldn't be dripping a lot of oil out.

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so like three drops of oil outta that tube could mean worn rings possibly??? wouldnt the bike smoke if that was the case because mine runs absolutley perfect other then the drips.

im just asking again cuz i just really hope i dont have to get new rings

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If you haven't rebuilt the top end then it could need it. The bike is almost 8 years old so depending on how much it was ridden, it is likely that the top end is worn out.

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so like three drops of oil outta that tube could mean worn rings possibly??? wouldnt the bike smoke if that was the case because mine runs absolutley perfect other then the drips.

A few drops of oil in the first 5 minutes of run time is cause for concern. I'd first check the oil level (or just change the oil) and see what happens.

Worn rings will cause a bike to smoke, if it has dino oil ran in it. Most synthetics (that I've seen) will burn oil without much or any smoke. Big bore 4 strokes have so much power that its hard to tell when they do need rings. Plus, the oil control rings should prevent (oil consumption) or smoking, it the compression rings that cause the blow-by.

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Three drops of oil may very well mean nothing. Certainly not something very serious.

Combustion blow by that results in a net outflow of gases through the breather is from combustion gases going past the compression rings, and it doesn't mean that oil is necessarily getting past the oil rings and into the chamber, so blow by and oil smoke aren't always correlated. Still, it's an older bike, and it wouldn't surprise me to find out that it could benefit from new rings, even if it doesn't need them in the strictest sense.

Be sure of the oil level, as mentioned before. It can only be checked accurately after the engine has been run for at least 3 minutes, and has been shut off for no more than 10. A minor excess of oil will cause nothing, since it's a dry sump system, and the level in the tank has nothing to do with the oil level in the engine. But, if there is so much oil that the tank completely fills, the engine will be unable to scavenge the crankcase completely, and blowing oil out the breather will be one result.

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Thanks for the info guys i was gettin concerned about the rings but it was to much oil after all

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