With that much of a downhill drain, I can't imagine there being much (if any) crap being blown out through the breather filter. If you run the drain line behind the heel guard with a small bottle (energy shot type) and then run the breather line up to the box, then there won't be any liquid or vapor to travel into the box.
How-To: Crank Case Breather Mod (with pics)
- Thread starter Urban_Assault
- Start date
Help Support Buellxb Forum:
From Erik Buell regarding breather re-route issues:
My question: What types of issues have you seen with the breather re-routes?
Erik Buell: "Related to fueling: what comes out of the breathers does affect the fueling of the engine. The ECM is calibrated for the breather. By having them plumbed into the airbox (like stock) and then pulling them out you can immediately see are reaction on the feedback fuel. Over time this can cause the bike to learn an inappropriate adaptive fuel value.
It is unclear if that vapor contains a hydro carbon and the engine is burning it in place of fuel, or if those fumes displace oxygen reducing the amount of fuel the engine needs.
In addition, if the breather is not allowed to "breathe" properly, you can build up crankcase pressure which will force oil into the combustion chamber. There is a lot of airflow through them, and normally the breathers get to breathe through the full surface area of the air filter. If the breathers are capped with a tiny filter, as we often see, this causes issues."
My question: What types of issues have you seen with the breather re-routes?
Erik Buell: "Related to fueling: what comes out of the breathers does affect the fueling of the engine. The ECM is calibrated for the breather. By having them plumbed into the airbox (like stock) and then pulling them out you can immediately see are reaction on the feedback fuel. Over time this can cause the bike to learn an inappropriate adaptive fuel value.
It is unclear if that vapor contains a hydro carbon and the engine is burning it in place of fuel, or if those fumes displace oxygen reducing the amount of fuel the engine needs.
In addition, if the breather is not allowed to "breathe" properly, you can build up crankcase pressure which will force oil into the combustion chamber. There is a lot of airflow through them, and normally the breathers get to breathe through the full surface area of the air filter. If the breathers are capped with a tiny filter, as we often see, this causes issues."
Baal
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I'd have a similar question. While I would no doubt defer to Erik's engineering expertise in general, and his knowledge of these bikes in particular, it was my conclusion that the FI system was unable to deal with the fluctuations in airflow caused by the breathers. Eliminating those fluctuations = smoother low speed running. Rerouting the breathers is not a Buell exclusive; I've read about it as a common practice for many OHV V-twins. Doesn't make it "right," but it does mean a lot of owners do it for the same reason we do.
Stevenc150
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I've had mine done for going on 3 years - no negative effects, only positive as it smoothed out my idle and almost cured the "hiccup".
Here's what I've researched (notice some may be here say as you can't believe everything you read on the internet):
"
The breather re-route should not hurt your engine as far as crankcase gases no longer being drawn into the intake - even cars before emissions were in place, just let crankcase fumes/pressure escape to the atmosphere.
However, the vacuum produced by the intake will create a negative pressure environment in the crankcase and help evacuate gases and moisture. Additionally, depending on how much vacuum exists, the rings *could* seal better, leading to less blow-by.
Another method used to create negative crankcase pressure is by placing the vent into the exhaust at an angle, where the passing exhaust gases pull the garbage from the crankcase via the venturi effect. Notice that in this case, an oil mist/air separator is used to prevent oil from entering the exhaust system.
"
Over the weekend I have decided to leave the vent going to the intake, however I have added an oil-mist/air separator and catch can (which I have might have to improve on a bit) between the vent and the intake, much like pamver posted a few posts ago. I have left both lines going into the intake, but added a much less restricting filter to each hose. I will be checking these two filters to see how well my solution is doing by catching the oil-mist.
A write-up with pictures will soon follow in a new thread.
*Flame-suit on*
Ben K.
"
The breather re-route should not hurt your engine as far as crankcase gases no longer being drawn into the intake - even cars before emissions were in place, just let crankcase fumes/pressure escape to the atmosphere.
However, the vacuum produced by the intake will create a negative pressure environment in the crankcase and help evacuate gases and moisture. Additionally, depending on how much vacuum exists, the rings *could* seal better, leading to less blow-by.
Another method used to create negative crankcase pressure is by placing the vent into the exhaust at an angle, where the passing exhaust gases pull the garbage from the crankcase via the venturi effect. Notice that in this case, an oil mist/air separator is used to prevent oil from entering the exhaust system.
"
Over the weekend I have decided to leave the vent going to the intake, however I have added an oil-mist/air separator and catch can (which I have might have to improve on a bit) between the vent and the intake, much like pamver posted a few posts ago. I have left both lines going into the intake, but added a much less restricting filter to each hose. I will be checking these two filters to see how well my solution is doing by catching the oil-mist.
A write-up with pictures will soon follow in a new thread.
*Flame-suit on*
Ben K.
Yes. I put up my write up under the DIY section. Notice that some of the air will still be dirty just from crankcase fumes and some unavoidable blow-by, however most, if not all the oil mist will be gone. I can report back after the end of this week or the next when I check the filters at the intake.
Come to think of it, I think I need to do this to my BMW - I haven't looked into the intake manifold yet, however after almost 100k miles I'm not holding my breath for clean runners.
Come to think of it, I think I need to do this to my BMW - I haven't looked into the intake manifold yet, however after almost 100k miles I'm not holding my breath for clean runners.
I recently did this mod and I found a lot of the suggestions in this thread to be overly complicated and aesthetically deficient (seriously, a beer can?)
From the breather tubes exiting the heads I ran the combined tube straight back through the hole to the under-seat area.
There I put in another T and ran one hose uphill to a breather filter and the other downhill to drain by the brake master cylinder.
The clearance looks tight in the picture, but there's actually a good inch between the hose and the drive belt.
The only thing I'm worried about is whether the seat is pinching the hose shut and whether any oil mist will make it to the filter and lube up my under-seat area.
I'll check out both of these items tomorrow.
From the breather tubes exiting the heads I ran the combined tube straight back through the hole to the under-seat area.
There I put in another T and ran one hose uphill to a breather filter and the other downhill to drain by the brake master cylinder.
The clearance looks tight in the picture, but there's actually a good inch between the hose and the drive belt.
The only thing I'm worried about is whether the seat is pinching the hose shut and whether any oil mist will make it to the filter and lube up my under-seat area.
I'll check out both of these items tomorrow.
Stevenc150
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Mine's under the seat and no oil mist, but I left the drain end open. He just needs to make sure to drain regularly.
DrogeN Omen
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looks like I'll need to do this for my bike...
found quite a bit of oil and sludgy stuff in my air box.
found quite a bit of oil and sludgy stuff in my air box.
Yeah I'm checking under and around the air filter every time I ride.
Two days commuting to work and no film that I can detect so far.
If it does become an issue I'll simply buy some more tubing and relocate it elsewhere.
I'll give it a chance in this location first, since it's definitely the stealthiest one I can think of.
I may also think about putting a breather in the airbox like above, outside of the filter.
Two days commuting to work and no film that I can detect so far.
If it does become an issue I'll simply buy some more tubing and relocate it elsewhere.
I'll give it a chance in this location first, since it's definitely the stealthiest one I can think of.
I may also think about putting a breather in the airbox like above, outside of the filter.
everyother_time
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ok I haven't been on here in a while, but I've noticed that my catch can hasn't caught anything, and the tops of my heads are now pretty dirty and oily... did I do something wrong? I'll submit pics later. but I followed the instructions to a T! I hope I didn't blow anything out or anything like that. Help a brotha out!
everyother_time
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Oh and one more question, are the head tops (the plastic R2D2 looking things at the top of the Heads) suppose to be loose? if not... how do I tighten them down?
Stevenc150
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Until the pics, there's only speculation - but if #16 & #17 aren't seated in properly, oil spray can get out there, or if you're hoses have come lose from #17.
