[ssg]

Today I noticed that there were a few cracks on the breather pipe of my Royal Enfield 500 CC. So I decided to change the breather pipe. The breather pipe which the dealer gave me was larger than the original one. So I cut the breather pipe which matched the length with the original one. The original pipe has 2 ends bend (the points of attachments), but my replacement pipe is straight though securely connected at two ends with clamps (air filter box end and crack case).Will there be any problem? (I am finding no difference after the change).
Thanks.

[High On Octane]

As long as the hose isn't kinked anywhere you should be fine.

[Craig McClure]

AH, my favorite subject. I routed my Longer Crankcase Breather Hose to the rear of the bike & plugged the air box inlet, then cleaned the GOOEY MESS out of the air box, & replaced the filter with a white pleated paper filter which is still clean & filtering. I have done this to all my motorcycles in the past decades since the DOT required them to regurgitate their own juices.
WORKS FOR ME.

[Magoo]

I'm about to replace my breather pipe today for pretty much the same reasons as the OP.
Will a simple straight through pipe suffice? I noticed a Hitchcocks diagram that has a 'bolt breather' in it (as well as a washer seal.
Is this just to limit oil blowback into the filter?

[pmanaz1973]

I'm with Craig on this one - I routed a longer version from india out below the swingarm with a PVC valve on the end.  Plugged my airbox hole and have don't worry about oil in my air box anymore.  Runs just fine.

[Scotty Brown]

About 6000 miles ago I sealed the air box breather hole and installed a longer hose under and along the frame to exit just above the license plate, and secured it with zip ties.  Also installed a duck bill breather ($4.00 fgt. pre-paid from India) on the exit end of the hose.  It fits very well.  Has given me zero problems.

[Arizoni]

I think it's rather odd that anyone would need or want to redirect the crankcase vent hose from its factory position on a UCE.  (The Iron Barrels are a totally different beast and have totally different problems with the vent.)

I replaced the stock vent hose with a clear vinyl hose on my 2011, G5, using the same outlet and clamps that were on the motorcycle sense it was new.
After riding well over 1500 miles, there is just the hint of oil mist collecting on the inside of the hose.

On my motorcycle there is so little oil vapor coming out that it would be totally useless as a chain lube.

Oh well.  I guess folks need to improve stuff, even when it doesn't need improving.

[JVS]

Haven't seen any oil in the air box filter assembly till now, luckily  The worst I've noticed was just a mild 'drip/leak' of oil after the first free service by the dealer four years ago.

[JohnDL]

I routed a longer version from india out below the swingarm with a PVC valve on the end.

That must be one hell of a long pipe! 

Sorry - I couldn't resist!

I've just replaced the cracked original with straight pipe too. Early deterioration of the pipe seems to be a common issue.

I checked the air filter at the same time and found no oil contamination, so routed the replacement back into the air box.

John 

[pmanaz1973]

I think it's rather odd that anyone would need or want to redirect the crankcase vent hose from its factory position on a UCE.  (The Iron Barrels are a totally different beast and have totally different problems with the vent.)

The factory position was venting oil ladened vapors into the airfilter box and shortening the life of the airfilter. In addition, I've noticed that the intake side of the throttle body (lack of a better term) stays much cleaner than my friends factory set-up on his 2012 UCE. At $25 plus shipping for a new air filter, it was a simple solution to reduce operating costs.  Again, I was not getting a great deal of oil in the air box, but enough of a film to try a different approach.  Easily returned to factory and with a total out of pocket cost of about $9.00   Besides, one of the reasons I own this bike is so I can tinker.

[Captwilly]

I believe that routing the breather line into the airbox is to keep any oil contained and not redirected to over the rear tire like the British bikes of the past. I would rather replace an air filter that have oil misting about the rear end.

 

[gremlin]

ever hold that breather up to your ear while the engine is running ?  WOW that's alot of air moving out AND into that vent.

its almost like every time the piston moves UP that pipe sucks in half a litre of air, then, when the piston moves down that half litre of air comes rushing back out again ....

I like the idea of an air filter for that vent. (or a balloon)

[Guaire]

ever hold that breather up to your ear while the engine is running ?  WOW that's alot of air moving out AND into that vent.

its almost like every time the piston moves UP that pipe sucks in half a litre of air, then, when the piston moves down that half litre of air comes rushing back out again ....

I like the idea of an air filter for that vent. (or a balloon)

Sounds like an aspect of the original design is to manage crankcase pumping pressure.
  After I noticed the cracking in the factory hose, I replaced it with a clear one too, ala Arizoni.

[adi-4004]

I replaced the stock vent hose with a clear vinyl hose on my 2011, G5, using the same outlet and clamps that were on the motorcycle sense it was new.
After riding well over 1500 miles, there is just the hint of oil mist collecting on the inside of the hose.

Oh well.  I guess folks need to improve stuff, even when it doesn't need improving.

My breather pipe too developed cracks close to the air box end. So the cracks were not visible for some time

Anyways I did exactly as Jim suggested here. The issue with the vinyl pipe is it gets kinks. So recently I replaced it with a RE breather tube which originally came with a bent at one end.

Another thing is I always use to see water vapor (but never oil) in the pipe. So it might be that the vinyl pipe was not tight enough at both the ends which let in outside moisture. This is just a hypothesis. Also I am a wannabe motorcycle mechanic so what I say might be completely wrong.

[Craig McClure]

I believe that routing the breather line into the airbox is to keep any oil contained and not redirected to over the rear tire like the British bikes of the past. I would rather replace an air filter that have oil misting about the rear end.

NO - Breather to Air Box is another over reaching stupid requirement of government agencies (EPA/DOT) run amok. 25 years ago they were routed out the rear of the bike, as I have continued to do for decades. Hose at the very rear of bike won't get oil on anything.
Those who want to assure their air intake / fuel delivery is not gummed up, CAN re-route the hose if they want to. We all have choices of how we manage our own property.