Why is oil dripping from a breather tube on my yz426
Posted 13 July 2007 - 10:24 PM
Posted 13 July 2007 - 10:29 PM
Posted 14 July 2007 - 05:44 AM
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.
Posted 14 July 2007 - 07:09 AM
im just asking again cuz i just really hope i dont have to get new rings
Posted 14 July 2007 - 07:24 AM
Posted 14 July 2007 - 07:30 AM
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.
Posted 14 July 2007 - 07:47 AM
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.
Posted 14 July 2007 - 04:05 PM