Excessive Oil from breather line
Posted January 24, 2005 - 04:23 PM
After yesturdays experience I belive a lot of oil is making it into and thru the breather tube while riding. I had a nice fresh oil coating on everything down that side of the bike at the end of the ride. I'm watching the oil consumption closely. It is not burning oil, no blue smoke; no smoke for that matter and runs excellent.
How much is too much oil to be loosing? I've read here that possibly the valve seats need to be replaced, correct? Anything I missed?
Thanks in advance. - Tim
Posted January 24, 2005 - 06:31 PM
Posted January 24, 2005 - 06:34 PM
Posted January 24, 2005 - 07:52 PM
Posted January 24, 2005 - 07:59 PM
These are dry-sump systems. When running, the frame reservoir will be full.
After sitting overnight, you will read nothing on the dipstick, as it will all drain down into the case.
Yamaha has set the dipstick length to show a correct reading when the engine has been shut off for that specific length of time. Check it any sooner and it's going to read high. Check it when the engine is cold and it'll read low.
Some people go absolutely nuts trying to get the level absolutely perfect after an oil change. I just dump in 1.5qts and make sure that it's ON the dipstick. If it's too high, being dry-sump, it's not that big of a deal. There will be a little more windage on initial startup, but once it's pumped into the frame it's fine.
Posted January 24, 2005 - 09:58 PM
I incorrectly said valve seats, I meant seals. If they fail what kind of symptoms would indicate a problem?
Posted January 24, 2005 - 10:04 PM
For excess oil from the breather line I would suspect PERHAPS excessive crankcase pressure due to weak rings (how's your compression?), but overfilling can also result in excess oil from the breather.
Like I said above, when stopped, the oil will eventually bleed down into the case. I am not 100% certain of the capacity of the case itself, but I strongly suspect that is IS sufficient to hold 100% of the oil in the system.
If that is the case, then an overfill could cause excess oil to be thrown into the top end by the timing chain at startup, which could find it's way into the breather tube.
I remember one guy saying that he had overfilled his YZ and he just had some extra oil coming out of the breather for a few rides.
Posted January 24, 2005 - 10:12 PM