breather filter

[philwarner]

I found a disconnected hose on my 96 California Mutt with individual filters and no air box and you guys educated me about how the breather system works and when the hose was open and I had it sitting on the carb when I was balancing them a few days ago, I was surprised at how much air was coming from it even at idle, so today I added a cute little breather filter I ordered from the local O'Reillys.  Rather than let it bounce around on the transmission I cable tied it under the right carb where I can keep an eye on it.  It even sort of matches the bike's color.  Hope it doesn't oil my right foot.  Time will tell, and time to take it for a new year's day ride.

[Mayor_of_BBQ]

Seems to me it would be best run 'uphill' under the tank or behind the steerer neck?  But what do I know....  On a smallblock, this would defiantly result in an oily boot. Please keep us updated.

[80CX100]

Seems to me it would be best run 'uphill' under the tank or behind the steerer neck?  But what do I know....  On a smallblock, this would defiantly result in an oily boot. Please keep us updated.

^^^^^ This^^^^^

I don't have one of those vent filters,(I use a Lemans style breather box), but if I did, I'd mount it uphill discretely along a top frame rail(under the seat, back fender/steering head etc) ensuring that any oil or condensate could flow downhill back into the engine.

It sounds like you're working through the bike and any issues, very nice looking ride 

fwiw

Kelly

 

[philwarner]

^^^^^ This^^^^^

I don't have one of those vent filters,(I use a Lemans style breather box), but if I did, I'd mount it uphill discretely along a top frame rail(under the seat, back fender/steering head etc) ensuring that any oil or condensate could flow downhill back into the engine.

It sounds like you're working through the bike and any issues, very nice looking ride 

fwiw

Kelly

I figured the system uses the frame tube as the oil separator and the hose ran "downhill" to the air box in the stock installation so this would not be that much different, except the air box was not contributing to vacuum at the hose.  I took a short ride around the Pea Ridge Military park today and nothing came out of the filter.  So far so good.

[80CX100]

I figured the system uses the frame tube as the oil separator and the hose ran "downhill" to the air box in the stock installation so this would not be that much different, except the air box was not contributing to vacuum at the hose.  I took a short ride around the Pea Ridge Military park today and nothing came out of the filter.  So far so good.

I'm not real familiar with the stock frame breathing set up, but if it runs uphill, any oil vapor condensate should run back down into the engine?

By placing the filter at a lower level, you run the danger of oil escaping and the sump level possibly going down over time.

If the oil level is lower and at low revs you may not notice it, but if the oil level is on the high side, especially at higher rpm, you may be creating a potential mess.

If it becomes an issue maybe there may be enough slack in the line, you could zip tie it up vertically between the pods in front of the battery compartment, fwiw.

Good luck with it

Kelly

[fotoguzzi]

Like the others said, I wouldn't leave it hanging down below the height of where the hose was originally mounted. As is you are just asking for a drip, probably not big but your boot might get a nice oiling on a long freeway trip.

[philwarner]

Like the others said, I wouldn't leave it hanging down below the height of where the hose was originally mounted. As is you are just asking for a drip, probably not big but your boot might get a nice oiling on a long freeway trip.

 Thanks for the concern and the warnings.  When I bought the bike the hose from the front of the frame was just loose under the seat where it had been removed from the air box and there was not a noticable amount of oil on the transmission; there was a little oil in the tube fitting that had gone into the air box but not a lot.  I'll just keep an eye on the filter to see if it gets oil logged over time.  I figured it is better out where I can see it than under the seat out of view.

[Chuck in Indiana]

A breather filter makes microscopically small oil droplets that go everywhere and attract dust.. making a measurable amount of dirt (Japanese grease mid)    from the old  manuals freakin *everywhere* under the tank. I've saved a couple of bikes that had that apparatus.
At any rate, you will not like it, Sam I am.. 
"Beware the grease mud, for under it lurks the skid demon."

[Kiwi_Roy]

 
I put a similar filter on my VII Sport only I hung it below the gearbox, I ran it that way for several years then re-installed the air box.
It got pretty oily but not overly so.
As to dropping the oil level in the sump, how is this any different to plumbing it to the airbox where it gums up a throttle body then gets burnt?

[80CX100]

I put a similar filter on my VII Sport only I hung it below the gearbox, I ran it that way for several years then re-installed the air box.
It got pretty oily but not overly so.
As to dropping the oil level in the sump, how is this any different to plumbing it to the airbox where it gums up a throttle body then gets burnt?

Hey Roy,    I thought the difference would have been gravity. The oil vapor would have to fight gravity working it's way up to a frame rail or air box, with most of it being pulled back down towards the engine.

      I can't remember the specifics, but I thought I recalled reading about someone with a poorly routed crank case vent hose doing a high speed run across the Mid West? and losing a fair amount of oil along the way.

      Kelly

[Kiwi_Roy]

Hey Roy,    I thought the difference would have been gravity. The oil vapor would have to fight gravity working it's way up to a frame rail or air box, with most of it being pulled back down towards the engine.

      I can't remember the specifics, but I thought I recalled reading about someone with a poorly routed crank case vent hose doing a high speed run across the Mid West? and losing a fair amount of oil along the way.

      Kelly

Sorry I don't remember exactly how it worked but I seem to recall the engine vented into the spine frame and there was one hose back to the sump and another to the air-box.
The bike used some oil but less than 1L per 1,000 km, the bike had 80,000 km on when I sold it. Like a lot of owners I thought pods looked cool so I had to do something with the vent line, I re-fitted the air-box after I came to my senses.
Leave the filter where you have it, fold up a square of shop rag and tuck it under to catch any drips
 

[philwarner]

Hey Roy,    I thought the difference would have been gravity. The oil vapor would have to fight gravity working it's way up to a frame rail or air box, with most of it being pulled back down towards the engine...  Kelly

If I understand the Cali system, the oil vapor does fight gravity by entering the lower end of the frame spine and exiting the upper end of the spine where it "goes downhill" via the hose to the air box while accumulated oil goes back to the sump via the large hose even lower on the spine.  What I don't know is if there is something inside the spine to facilitate the oil separation or if it is just an upward sloping tube.  I assume there would be a slight vacuum in the air box helping draw air from the tube VS no vacuum if the hose is vented to atmosphere assuming no "venturi effect" at the end of the hose.  I also assumed that if I put the filter end of the hose higher and there was oil exiting the top of the frame tube it would just pool in the hose.  I'll just keep an eye on it where it is and let the forum know if it becomes a problem.