I recently developed a oil leak predominantly on the left hand side of my engine. I discovered the problem and solution so I offer the information here in the event you develop the same.
I noticed a drip of a few oil drops on the garage floor. Upon inspection, oil was lightly all over the underside of the left cylinder head and it initially looked like the beginnings of a failed head gasket. I cleaned it off to see if I could better locate the source of oil.
After a 500 mile ride, the oil had returned to the underside of the left cylinder as well as towards the rear of the engine in the left side. I also noticed spritzed oil on the right hand side of the engine now as well.
So, I removed the tank, where I discovered the crankcase vent tube, after 8 years of riding here in Ohio winters and summers, had become stiff and brittle on the end, and the crankcase vent end of the hose was simply pushed onto the metal crankcase vent tube. Given its hardened condition, it was no longer tight on the tube, and in fact, had blown off for the most part.
The oil was from the oil saturated air passing out the crankcase vent tube which had covered the underside of the fuel tank and all the wires and hoses, with a fine misted oil which had dripped and run all over the left cylinder, giving the appearance of a blown cylinder gasket. (You can see the fine mist of oil on the left intake tract in the lower left of the photo.)
I cut 1 cm of the brittle end off of the crankcase vent end of the rubber “U” hose (the center tube going down the silver metal bracket), reseated it and crimped an Oetiker clamp on it. I then put another Oetiker clamp on the other end of the “U” hose where it connected to the air-box intake on the left (seen in the photo).
I checked the inside of the air-box and there was no oil. (This BTW, is why you must not overfill your crankcase, because the liquid oil will be blown right into the air-box via this hose setup!)
Everything is fine now. No more oil leak. Some degreaser and a good wash, and it’s just like new again!
If you develop a similar oil leak, you might want to check this location.
I noticed a drip of a few oil drops on the garage floor. Upon inspection, oil was lightly all over the underside of the left cylinder head and it initially looked like the beginnings of a failed head gasket. I cleaned it off to see if I could better locate the source of oil.
After a 500 mile ride, the oil had returned to the underside of the left cylinder as well as towards the rear of the engine in the left side. I also noticed spritzed oil on the right hand side of the engine now as well.
So, I removed the tank, where I discovered the crankcase vent tube, after 8 years of riding here in Ohio winters and summers, had become stiff and brittle on the end, and the crankcase vent end of the hose was simply pushed onto the metal crankcase vent tube. Given its hardened condition, it was no longer tight on the tube, and in fact, had blown off for the most part.
The oil was from the oil saturated air passing out the crankcase vent tube which had covered the underside of the fuel tank and all the wires and hoses, with a fine misted oil which had dripped and run all over the left cylinder, giving the appearance of a blown cylinder gasket. (You can see the fine mist of oil on the left intake tract in the lower left of the photo.)
I cut 1 cm of the brittle end off of the crankcase vent end of the rubber “U” hose (the center tube going down the silver metal bracket), reseated it and crimped an Oetiker clamp on it. I then put another Oetiker clamp on the other end of the “U” hose where it connected to the air-box intake on the left (seen in the photo).
I checked the inside of the air-box and there was no oil. (This BTW, is why you must not overfill your crankcase, because the liquid oil will be blown right into the air-box via this hose setup!)
Everything is fine now. No more oil leak. Some degreaser and a good wash, and it’s just like new again!
If you develop a similar oil leak, you might want to check this location.