The only time I get engine oil out of that breather hose is when I drop my bike on the right side while it's running.
That is a lot of oil and not normal. Is it possible for leaking piston rings to pressurize the crankcase and blow oil out the breather? I have never encountered this but you get a similar situation with a blown headgasket which pressurizes the cooling system and forces the coolant out. I suppose with rings leaking that much the bike would be burning oil. Other than that it almost has to be overfilled oil. I have the same bike, same year and I get NO oil out of mine. I like to run my oil level a touch high too, right at the top of the sight glass when vertical. Cam.
Wheelies, drops and high RPM's seem to be the major culprits, regardless of oil level. I did notice more oil out of the airbox running Rotella T6 than the Castrol 4T race syn that I'm running now, possibly because the Rotella seemed to foam more.
As far as I know, there isn't a reed valve, and the valve cover vents straight to the airbox. The big issue is that it's not like an inline 4 where the crankcase pressure is balanced, the crankcase sees huge pulses because there's only a single cyclinder.
There is a reed valve. It is surrounded by the cam chain down by the crankshaft. Reed valve damage is common with a cam chain that is too worn.
Hi everybody ! Just had the same problem with my 630. That began after 5000km service, lots of oil through the breather (to airbox) , but only while doin' wheelies. I've done high and long wheelies before and there was no such a problem. Dealer now has no ideas about it so I'll try to lower the oil level. Have no other ideas.
I don't remember about that breathing hose on 610, but I've put much more oil in it and had lots of high and long wheelies without a leak. Hope the dealer hasn't disassembled the bike )) Will try tomorrow to lower the oil level
Hi guys. I'm having the same issue with the oil in the airbox, and don't know what to do. I rode the bike at full throttle in or 5 h gear for 5 minutes or so and oil is coming out. Normally I would think it's something related to the engine, as in pressure escaping around the rings into the engine and pushing the oil out the breather hose. This would be expected on a worn out engine, but mine has 8000 km. And I remember once when the bike had only 2000 km and I dropped it quickly, was only in first gear but I hit an oil patch in the parking lot, the bike was on the ground for seconds only and it still dripped a lot from the airbox. There might be an issue somewhere, I just don't know where to look.
If the bike is on the right side, it's going to puke oil everywhere, as the valve cover vent is on the right side. Even worse if the bike is still running. What oil were you running? Did it foam at all? How high was your oil level in the sight glass?
