What is this one?

[darkangel_imp]

Hi all, tonight after a riding, I was looking around the bike and see this part (image attached), could anyone tell me what it is? Should I open and clean it because it looks dirty. Thanks!

[Cormanus]

darkangel, my Honda manual calls it a crankcase breather tube. There's another one under the engine on the left hand side of the bike. You need to empty it if it fills up. It's pretty easy to do, although I'm blowed if I can ever manage it without getting gunk all over the top of the crank case.

I find the easiest way to do it is to take the circlip off the top and take the whole pipe off rather than fiddling with the plug on the bottom. That's probably why I make a mess.

[mininsx_imp]

I check mine every time I do an oil change. There's usually nothing in them.

[Lord Popgun]

darkangel, my Honda manual calls it a crankcase breather tube. There's another one under the engine on the left hand side of the bike. You need to empty it if it fills up. It's pretty easy to do, although I'm blowed if I can ever manage it without getting gunk all over the top of the crank case.

I find the easiest way to do it is to take the circlip off the top and take the whole pipe off rather than fiddling with the plug on the bottom. That's probably why I make a mess.

Hey Cormanus, is your crankcase made of plastic and mounted right under the tank ? That one is for the airbox or cleaner or whatever you want to call it.

[Nortoon_imp]

Since we are looking at unusual engine parts. Does the oil drain plug on the CB1100 face straight down?

The reason I ask is the oil drain plug on the CB500XA I own faces backwards. If you undo it, hot oil sprays all over the center stand, rear wheel, and garage floor. None of it makes it into the oil drain pan under the bike. I had to buy a Fumoto oil drain valve to cure the problem.

[Lord Popgun]

[quote='Nortoon' pid='163349' dateline='1486139408']
Since we are looking at unusual engine parts. Does the oil drain plug on the CB1100 face straight down?

Yes. Look at this: Item 22 http://www.hondapartshouse.com/oemparts/...n-oil-pump

Oil drains into a pan very nicely

[the Ferret]

http://www.cb1100forum.com/forum/showthread.php?tid=202

[AzBob_imp]

darkangel, my Honda manual calls it a crankcase breather tube. There's another one under the engine on the left hand side of the bike. You need to empty it if it fills up. It's pretty easy to do, although I'm blowed if I can ever manage it without getting gunk all over the top of the crank case.

I find the easiest way to do it is to take the circlip off the top and take the whole pipe off rather than fiddling with the plug on the bottom. That's probably why I make a mess.

Hey Cormanus, is your crankcase made of plastic and mounted right under the tank ? That one is for the airbox or cleaner or whatever you want to call it.

Hey Cormanus, is your crankcase made of plastic and mounted right under the tank ? That one is for the airbox or cleaner or whatever you want to call it.
The PCV system vents to the airbox to re-burn stuff to meet EPA emissions standards, so yes, it's still a crankcase breather tube because that's where the PCV stuff originates.

[Lord Popgun]

OK, thanks AZbob! That makes perfect sense. I like my plastic crankcase theory better though

Standing by for abuse from Cormanus (deservedly so)

[Cormanus]

I'll let you off popgun. As you'll see I said "my Honda manual calls it a crankcase breather tube". I said that because it seemed odd to me that it would be sticking out of a part above what I always thought was the crank case.

So thanks, AzBob, now I understand better.

Mine, by the way, is often full.