Hyper on superbikes with oil leak - Ducati.ms

ed218 · Jun 14th, 2008, 7:27 am

I was watching racing a couple weeks ago and in between races I watched superbikes. I normally don't watch this show, but they had a hyper on it. The host said they usually don't use duc's because they need to be modified. He did a wheelie an got an oil leak. So what causes it.

**desmoworks** · Jun 14th, 2008, 11:23 am

Quote:

Originally Posted by ed218

I was watching racing a couple weeks ago and in between races I watched superbikes. I normally don't watch this show, but they had a hyper on it. The host said they usually don't use duc's because they need to be modified. He did a wheelie an got an oil leak. So what causes it.

Nobody will be able to answer this questions without inspecting the bike - there are far too many variables.

speedfreak · Jun 14th, 2008, 11:25 am

The pcv valve or the crankcase vent as some call it. The engine cases on some bikes ( the HM included) are not designed very well. When the engine is stood straight up, as in a balance wheelie, engine oil will gravitate towards the bottom. With the engine stood up the vent happens to be below the new oil level. Pressure inside the engine will push oil up the vent tube into the airbox. From there the oil will either get sucked into the engine and burned (smoke out the exhaust) or run out the drain tube and produce an "oil leak" on the ground.

Alot of engines are designed with a sort of trap casted in the cases to allow pressure to vent without allowing oil to actually reach the vent when the engine is stood up. Another option is to install some sort of catch can. This is a little canister that allows the pressure, and oil, to come up the vent tube into the bottom of the canister and then the pressure to vent out the top of the canister to the airbox while capturing the oil. Once the pressure is gone (or engine shut off) the oil will drain back to the motor.

As long as you keep an eye on your oil level this is usually not harmful to your motor. (As long as you are not starving the oil pump, but that is another discussion) It could be harmfull to someone following you if you set a long wheelie down and start dripping oil onto the ground out of the airbox drain tube.

crashman · Jun 14th, 2008, 4:25 pm

I think you have to take anything said on a show that is by stunters for stunters with a grain of salt.

cincykid · Jun 14th, 2008, 9:58 pm

I had asked the same question. If you do a search on here you will find it. Jason (the host) was trying to pull a 1 mile wheelie and after about a 1/4 mile across the bridge he got a puff of smoke and after he set it down, a little bit of oil came out the overflow. I think this is what you are referring to. The guys bike he was riding is actually on this forum. Actually, here is the link to the thread: Did anyone see "Superbikes" on speed the other night?

**desmoworks** · Jun 14th, 2008, 10:31 pm

So it is not leaking oil, only puking it out. Two completely different things!

speedfreak · Jun 14th, 2008, 11:06 pm

I was looking on my buddys 94 Monster and even it has a catch can. I think Ducati tried to get by without one on the HM because their is no room for one.

**desmoworks** · Jun 15th, 2008, 1:34 am

Quote:

Originally Posted by speedfreak

I was looking on my buddys 94 Monster and even it has a catch can. I think Ducati tried to get by without one on the HM because their is no room for one.

I think that is correct... all of the other models I can think of have them. The trick setup on the 748-998 bikes was a super big under seat carbon fiber breather box that increased crank case volume. This in combination with a corse breather valve let the oil flow both directions no problem as it was supposed to add a couple of ponies.