| Author | Message | ||
     Tolndakoti |
Bear with me, as I'm still learning about Engines. I bought a Buell M2 that came with an S&S air cleaner crank case breather kit  1 - I took it off and there seems to be a little oil coming out. Is this normal? It seems to be expected behavior, as the hose connected to the breather kit is long enough to drain liquid. 2 - Let's say that this normal. I'm replacing my S&S air cleaner with either the Arlen Ness Big Sucker II or the Maliair. Both options seems to offer a crank case breather incorporated into the carburetor bracket into one unit. So...where does that draining oil go? | ||
| Tolndakoti |
Found a video on the Crankcase breather kit installed. https://www.youtube.com/watch?v=Qk5DSYFBJfQ | ||
| Kilroy |
You drain it to a catch can that you can drain later. Pegasus Racing sells a neat little aluminum one that works well and is cheap. Stock configuration drains the "oil" back into your carb/intake to be burned by the engine. | ||
| Kilroy |
PS you are going to have to bend the breather tube a little bit to get that to fit on your engine. | ||
| Tolndakoti |
>Stock configuration drains the "oil" back into your carb/intake to be burned by the engine. Wont that just make my Carb/engine Dirty? | ||
| Natexlh1000 |
Yes it will make your carb dirty. Most of that comes out of the breather is water with just enough oil mist to make a lovely mess of your right pant leg and shoe. I finally gave up and ran mine to a tube near the exhaust outlet. Now my rear rim gets the spritz. It's more classy to run a catch can but I was much too lazy to do anything like that. | ||
| Alfau |
A clean air filter is essential for the motor to run smoothe. The oil from that breather gunks the filter up fairly quickly affecting the air flow. A catchcan reduces the need to clean the air filter so often. Diverting this oil onto the road is illegal and not a real good idea to grease up your rear tyre. Air in air out needs to be balanced. If you change the air in to a more free flowing you really should inlarge the exhaust to balance the air flow out. Hope that makes sense. | ||
| Tolndakoti |
I guess what doesn't make sense for me is: why design a crankcase that spits out oil, I don't remember having this problem on non-Harley engines. | ||
| 01x1buell |
its a harley they do that. | ||
| Greg_cifu |
Actually, ALL engines do this. Most of them have more elaborate breather systems to where you don't notice it. The problem is piston ring blow-by: combustion gas that leaks past the rings. Piston rings are good but, there is almost always some leakage at high loads (full throttle). That expanding gas gets into the crank case and has to go somewhere to get out. That's your breather. All of my thumpers do it. Some of them contain the mess inside the airbox and the average owner never notices it. My Excelsior Hendersons do it. My BMW boxers do it, though they also contain it in the airbox and eventually burn it so owners don't notice. Probably the worst I've seen was the 0290 Lycoming in my friend's airplane. Not wanting streaks of puked oil on his fuselage, he designed an elaborate but, effective breather, separator and catch system. The stock airbox on our Buells dealt with it. Some people think they know better than Buell so they take the airbox off and replace it with aftermarket stuff. OK, they're the engineer now: they have to figure out something to do with blow-by gas coming out of the breather. | ||
| Jolly |
switch over to XB style rocker boxes, plug the holes that set up bolts into, the new rocker boxes breath out the top of the cover and are much cleaner and more efficient and less prone to leak since there is only one cover (the spacer is removed), then run a line from the PCV style breathers in the top of the covers to a catch can. have done it two of my bikes...money well spent! buy the full set up from Al at American Sport Bike, plus a catch can. | ||
| Reepicheep |
The crankcase breather typically goes inside the filter. It's not like its pouring oil in there, it's an oily mist, and it's only there when the engine is running and the carbs are drawing a lot of air through the filter. Stock Buells run great that way, but if you want to run a catch can and deal with the spooge that's your decision. Saab had to go through 6 revisions of their crankcase breather system on their circa 2000 motors before they found a setup that wouldn't sludge. | ||
| Ratbuell |
All of my bikes run stock breather setups (I changed my S2 to XB rockerboxes to help reduce leaks, when I did the Thunderstorm top end). They don't "dump oil" into the carb. They don't "make them filthy". They don't dirty your filter because they exit inside the filter, right into the throttle neck. They don't cause running problems. What they DO do, is make for one less thing to worry about - no catch can to worry about draining. They also lubricate your throttle plate and shaft - those items are "dry" in the carburetor (or EFI, if you have an injected Buell) as far as lubricants are concerened. Fuel is NOT a lubricant; there's a reason fuel-like substances (diesel, kerosene, or even gasoline) are ingredients in parts washer solutions. I...prefer to keep my carburetor lubricated and in good working order. And yes, every internal combustion engine has a breather setup. Cars, they're called the PCV system (Positive Crankcase Ventilation). Usually a valve or port in a valve cover that breathes...you guessed it...into the air intake. P...C...V. PVC is plumbing pipe. Sorry, just a pet peeve  |
