| Author | Message | |||
     Norrisperformance |
What are the pros and cons. | |||
| M1combat |
I'd think someone developing and testing parts would know that but... The breather tubes being routed inside the filter will "recycle" oil through the engine. This causes carbon buildup on the valves and an oily film throughout the intake tract. It's purely an emissions thing and an engine should NEVER be subjected to such punishment... That said... I left mine stock but I'll do something about that soon. | |||
| Rigga |
recycled oil through the inlet is more likely is cause increased pinking..... and as these bikes can suffer from this at times re routing the breathers out of the airbox helps to reduce this situation,mine hasn't done it since | |||
| Hogs |
Norris, There are no PROS Buddy Just CONS LoL Hows the project coming along :-) | |||
| Smokie |
no oil seems to come from the breathers anyway | |||
| Jan_lee |
In conversation with Rich Conrad of Innovative and Racingmotorcycles.com he said to leave the breathers in the air box we had ours on the race bikes routed to a catch can behind the front fairing. he said that by putting then in a catch can the engine is not venting correctly those rockerbox breathers are essentially pcv positive crankcase ventilation and by having them in the air box it creates a vacum through the engine. we were told this is the best way to run the breathers as for in or out of the filter i would say out but be smart get the k and n and clean it regularly. | |||
| Hogs |
DUMP the hoses out of the air intake stream into a catch can and filter with k&n filters there... No ones needs that mess in there its a pollution factor only | |||
| Whodom |
What Jan says is true- the breather tubes do serve to suck blow-by gases out of the crankcase. If they stay there, they condense in the oil and speed up its deterioration. I think my old 1983 Honda Ascot VT500FT (500cc v-twin) has a good setup that's the "best of both worlds". It has a catch can (actually a plastic box) located underneath the air filter box, which is under the seat. The breather tubes from the valve covers are routed down to the catch box. The top of the catch box is vented to the bottom of the air filter box. The oil and "funk" wind up in the catch box, you drain it via a plugged hose when you change the oil. The fumes get sucked into the intake and get burned up in the engine. No deposits on valves, intake, etc., but no funk in the engine oil either. Why not install a catch can down low on the Buell, but instead of putting a filter on it, route a hose from the top of the catch can back up to the airbox? The funk winds up in the catch can, but you still retain positive crankcase ventilation. | |||
| Hywl_fawr |
How about this, Small plastic box in the rear left section of air box outside filter acting as catch tank, 2 breather hoses into top. 1 vent or hose out of top to origional breather hole in bottom of filter base to create vaccume, 1 drain hose from btm of box to under bike with plug, there could be some sort of baffle in the box like mesh to encourage the oil in the mist to condense, the sort of box I am thinking about come from radio shops and have a screw fixed lid Please excuse my poor drawing.
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| Cruisin |
I seem to remember an article in Battle2Win regarding the breather tubes. They were testing the different little gimmicks that you can put on and dynoing each one. If I remember correctly, the conclusion was that routing them anywhere other than back into the air intake gave a better dyno run (in other words none of the little gimmicks worked). I've got the stack of Battle2Wins at home...I'll try to dig up the article. | |||
| Typeone |
I'm with Jan too, my '66 Porsche 912 (with a sweet little flat-4 air cooled motor) has a similar setup where the breathers run to the top of the air filter setup on one of the carbs creating a slight vacuum. I've seen guys run a small in-line filter to help with the nasties but it might be over kill in some situations. I'm leaving my tubes stock. (Message edited by typeone on April 28, 2005) | |||
| Bomber |
whatever comes outa the breather houses (oil mist or not) surely ain't the same composition as the air from outside the rest of the motorcycle -- me, I'd route the house elsewhere, making sure the aircleaner and engine wasn't getting the dubious benefit of air that had been routed through the lowere end of hel, er, the engine . . . . . . pro leaving em where they are . . . .er, it's stock, they don't puke as much as the tubers did, er, it's stock (if ya like that kinda thing) ;-} | |||
| Race_pirate |
I made a small shield just forward of the breather tubes BUT they are still in the box. Prevents splatter on/in the velocity stack. Drag cars actually hook up a suction pump or one way valves in the header collectors to create a slight vacuum in the case/block. No positive pressure(or less) under the piston on the down stroke. | |||
| Sweetp411 |
I put on that open air box conversion kit from American Sport Bike, and they supplied me with some breather hose, u take the two hoses from the two PCV valves and splice them with a brass T splice fitting, then run the run off hose down the front of the bike into a K&N catchcan that sits in my front chin cowl. It actually looks kind of cool, the little catch can that is, got some pics of it on my photo site http://photos.yahoo.com/sweet_p411. It wasn't that hard to do. Then where the old short breather hoses came up thru the lower airbox cover, you have to glue these rubber nuts and rubber washers with some rubber silicon sealant, and that is where your bolts screw into for the air filter cover (Message edited by sweetp411 on April 28, 2005) | |||
| Al_lighton |
With an inline 4 or parallel twin engine, I might buy the argument that leaving them in the airbox helps scavenge the crankcase gasses better. Inline four engines have one piston going up while one is going down, and are therefore constant volume crankcases. So the only pressure in the crankcase is ring blowby and increase temp pressures. With our single crank pin engines, there is significant pumping going on below the pistons in ADDITION to the blowby. The PCV valves have a one way check valve in them that theoretically keeps the return air from coming back in. But there is still a pair of pistons going down on every stroke that push blowby out. I think the amount of vacuum at those rubber hoses pales in comparison to that pumping. I've seen Aarons test results in B2Win years ago on the tuber/XL engines, they make perfect sense to me. Routing them out is the way to go. Al | |||
| Al_lighton |
"If I remember correctly, the conclusion was that routing them anywhere other than back into the air intake gave a better dyno run" I don't think you are remembering correctly. The conclusion certainly was that the gimmicks that put a second inline check valve in series with the existing ones did not do anything. BUT, routing the breathers out of the crankcase was good for 1-2 ponies on top. It is less to do with oil in the breathers, and more to do with the fact that the breathers are recycling air that has already been burned (ring blowby) and therefore has little O2 left in it. That recycled air dilutes the combustible intake charge with some incombustible stuff. Routing out is the way to go. Al | |||
| Cruisin |
Al, that's what I was trying to say - that they had proved via a dyno that routing them out was the better way to go. Theories and ideas are great, but it's always better to go by the numbers. And I'm pretty sure you are correct - recycled air doesn't burn as well. | |||
| Norrisperformance |
Ok The catch can I'm designing will have the option to run a hose back to the air box or to a small filter. Just looking for feed back, and as always, this is the best place to get it. Thank's | |||
| Race_pirate |
So...if you leave the breather hoses in the air box you dont have to oil your spark plugs.... | |||
| Al_lighton |
Christopher, DOH!!! You're correct, I misread your wording, my bad. Yes, that's what he said, NOT into the intake always gave better results. Peak difference was 3.8HP at 6000RPM in his testing, but in the upper RPM ranges, 1.5-2HP was typical for the breathers routed to atmosphere vs routed into the intake (using a Kuryakyn spacer on the intake) The amazing thing was that he plugged them completely for one test. That STILL outperformed the routing the breathers into the intake. Diluting the intake charge with burned air robs power, period. And Aaron knows how to run a dyno and not get fooled by heat soak and repeatability variances. I'm very curious to know the impacts of the reed valve that exists in the XB engine that does not exist in the XL engine. Between the flywheel chamber and the cam chest, the XB's have a reed valve that I can only presume is to allow for blowby to get from below the pistons into the cam chest, then up the pushrod tubes to the rocker boxes, thru the PCV valves and out to the airbox or the atmosphere if the breathers have been removed. This would seem to make the flapper valves in the plastic PCV valves be redundant for dealing with the blowby. As Aaron's testing proved, two serial one way valves don't buy you anything. So why are they there? Is there something I'm missing? Al | |||
| Hogs |
Norris, Up to you pal... But I think keep them hoses out of the air box 100 Percent, They are just there for the pollution or whatever one calls it , emissions my spelling sux ...But I for one Will never run VENT hoses into my air intake stream ,Causes all kinds of plms. in the long one.... Hows the box coming btw ??? | |||
| Norrisperformance |
Hogs Trying to get some custom covers finished for GodSpeed in Cali. Discovery Channel starts filming Tuesday for a six hour series called Embedded in America I've got some good feed back from you guys. I'll start working on it next week. Trying to get the nitrous kit finished also. I'm 5 to 6 weeks behind in work right now. I maybe getting ready to move the shop and hire some help to keep up. (Message edited by norrisperformance on April 28, 2005) | |||
| Hogs |
HEy NOrris, Good stuff its good to be Busy ,$$$$ Hey move the Shop down Florida somewhere I`ll meet ya there and Hire me So I can get out of this damn Eskimo LIving I can clean Floors really good But I`m Expensive LoL | |||
| M1combat |
The reed valve... Isn't that generally covered in oil? I think that oil gets pumped through that by crank pressure and is returned to the oil pump to be pumped back to the swingarm? | |||
| Outrider |
If anyone saw the lard I had to dig out of the EFI intake when I installed a catch can on my X1, much less the weird liquid that I drain out of the can, I don't think there would be a discussion about the benefits of using one. Just an opinion. YMMV  | |||
| Kaese |
I had that problem with my tuber that had a Forcewinder and I never could get it right. Since I rack up the miles rather quickly, the best solution I found was to run it back into the intake. The tuber puked so much oil, that you had to remember to empty it once a week. Once catch can got full, it would start coming out the vent. It was just a pain. That was some of the nastiest oil I have ever seen or smelled! I'm leaving mine alone, I don't want the hassle. | |||
| Outrider |
Kaese...Thanks for the laugh about the "hassle."! I usually drain the catch can when I check the oil at the end of a ride. Only problem is, this year I forgot the drill and discovered oil all over the left side of my engine and leg when I got home from yesterday's ride. What a mess that was. At first I thought I blew a gasket. You can imagine how relieved I was when I learned is was due to a minor brain fart. Still am glad it isn't going back into the engine. I might change my mind if Buell makes a statement that it is beneficial to the life of the engine. However, I can't think of one good purpose for it other than the EPA. | |||
| Kaese |
My tuber had the white wheels and I ran the catch can and the filter underneath the tail. | |||
| Wyckedflesh |
The crank breathers on the XL engines sit in a bad location and as such tend to get drowned in oil. The breathers on the XB engines sit in a different location that gets alot less exposure to oil. Now, I have not had an instance in 18000 miles to find any hint of oil residue within my intake. Some have, some haven't. Those running K&N filters might want to ask themselves "Is the oil I am finding in the intake from my breathers...or from my filter?" Just some food for thought. | |||
| Outrider |
Wycked...I know what you mean. Especially since one of the best cures for the tubers is the conversion to the XB rocker covers. One of these days I'll get around to making the swap but in the interim, the catch can will suffice. | |||
| Al_lighton |
Don, You are correct on the reed valve, I think. Oil control only. I spoke for a while to Justin at NRHS about this today, and he corrected me that very little of the blowby gets up to the top thru the pushrod tubes, as the lifters are in the way for that passage. Most of it goes up the oil return tubes at the rear of the rear cylinder and front of the front cylinder. So not much blowby is crossing the flywheel chamber to the cam chest. There is substantially less oil in the XB breathers due tot he location of the breather passages, but it isn't just the oil that concerns me with it's presence in the airbox. An engine in good shape has 3% or so ring blowby (already burned air/fuel mix). That goes down past the pistons to the flywheel chamber and is pumped up the oil drainback passages into the rocker boxes and out of the PCV valves. If it is going into your airboxes, indeed, being sucked there, it must dilute your intake charge by a similar volume. The worse your ring seal is, the larger the horsepower robbing effect it will have. Theoretically, the check valves in the PCV valves should allow airflow only out of the engine. So after the first couple downstrokes of the piston, the only air being pumped out of the engine IS the ring blowby. Why would you want it to be sucked into your airbox, other than for emissions reasons? If sucking on it somehow reduced pumping losses, that might be a reason. If pressure was somehow able to build up in the crankcase otherwise and potentially destroy seals, that might be a reason. But I don't see either of those as being an issue with the XB engine design. IL4 engines with constant volume crankcases don't have any natural pumping out of the crankcase. They might benefit from sucking the blowby out, I guess. Note that all the ultra high RPM engines have ports for minimizing the pumping losses that occur between adjacent cylinders as the blowby is pushed back and forth by the under piston pressures, but there is no net pumping out of the crankcase, so perhaps sucking it out is a good thing for those. High performance dragster engines use negative pressures in the exhaust system (bernoulli effect stuff) to scavenge the breathers. But for our engines, it sure seems to me that the dilution of the intake charge with incombustible air is the primary reason for removing the breathers from the airbox, and that the scavenging gains wouldn't offset the dilution losses. Or not. I don't have ready access to a dyno to test this stuff easily. Aaron's testing on the XL engines is good enough to convince me to remove them. He saw nearly 3 HP up at the top, which, for a 100HP engine, would correspond to a 3% blowby. It seems reasonable to assume that getting that blowby out would result in measurable gains. Al | |||
| Shotgun |
Good words Al. Beyond that, when I drain my Puke can, I have a water-oil spurge. Why would I want to put that crap back thru my intake system? To me it's like saying, ok, go ahead and put 3% water-oil mix in the fuel tank. Who would do that to a good running bike? | |||
| M1combat |
I wasn't saying that I prefer to route the tubes into the intake  . Just that the reed valve in the lower portion of the case is a real piece of genius. It would even help the oil pump be more efficient and rob less power . (Message edited by m1combat on April 29, 2005) | |||
| Buellboardtrackracer |
On softtails,roadkings,etc,etc, The idea is to to have the breather hoses to run up hill to prevent the oil mist from running out. Use automotive PCV units or a small air filter. The engine does not like dirty air and the intake has nothing to do with the breather venting. The Breather venting is happening on it own by the pistons going up and down in the cases. That is the purpose of a breather to relieve the that pressure of the pistons going down. It is a EPA thing to vent the dirty into the motor not the atmosphere. | |||
| Xbolt12 |
I left mine inside the filter when I did the airbox cut, simply because I don't want an oil mess on the bike. I do remember that even on pre-smog control cars, they would vent the crank into the engine, or even with a "road-draft" tube-which is simply a tube cutoff at an angle and protruding below the engine. This creates a vacuum at speed. As I recall the engine oil lasts longer this way because it is contaminated less by blowby. That may not be an issue with those of us changing oil at 2500 miles, but it might be worth evaluating. I have no doubt that I am losing some horsepower, but I would question that it is a couple on the top. Might that be only on a highly modified engine producing more base hp anyway? xbolt12 |
