Crank Case Vent Upgrade!

[skydoc_17]

At the end of the riding season last year, I bit the bullet and Installed a K&N Air Filter. Since the weather has been so bad here, (snowing again today, 3 ins. by morning) I have had an extended amount of time to do all of the things to my 87'VR that I would never do during the riding season. I removed the Air Box Cover and to my surprise there was a BIG messy oily spot on my brand new filter where the Crank Case Vent Tube enters the Air Box. I was not happy. Well the old 87'VR has 75,000 miles on it now and I figured that there is probably going to be some blow by. I remembered that on my 86' V65 Magna, before I rebuilt the engine I had the same problem and added a Crank Case Vent Filter and disconnected the Crank Case Vent Tube from The Air Box. So, I did the same thing on the 87'VR. The pics below show the plumbing that I removed, How I plugged the two holes in the Air Box, The New Vent Filter, and the final result. Any Questions, Feel free.

Earl

 

 

Edited November 28, 2019 by Freebird

[fixit3546]

looks good, where did you find it???

[Texaskid]

Hay Earl,

Don't forget to put your plugs back on. Nice job.

[skydoc_17]

Hey Bill,

Thanks for the tip, I did remember! Had my Ensure today, LOL.

I got the vent filter off of ebay, James. I guess I should mention that I had to remove the very small water line that is in front of the crank case vent tube coming out of the engine to get the vent filter in there. If your radiator is full when you pull that line it won't be after! I had a pair of rubber plugs handy and was able to plug off both the line and the nipple in the engine.(red cap plug in last pic) It was a gusher there for a moment or two but it made it a lot easier to get the vent filter in that tight space.

Earl

[6m459]

As I understand things, the OEM crank case vent tubes go to the air box so that the vacuum created by the combustion air flow, will draw combustible gasses out of the crank case and into the combustion stream.

 

With your new setup, you have ambient air pressure inside and outside the crank case which won't vent the combustibles.

 

I don't like the looks of it, I'll be keeping the OEM setup on my bike thanks.

 

Brian H.

[saddlebum]

As I understand things, the OEM crank case vent tubes go to the air box so that the vacuum created by the combustion air flow, will draw combustible gasses out of the crank case and into the combustion stream.

 

With your new setup, you have ambient air pressure inside and outside the crank case which won't vent the combustibles.

 

I don't like the looks of it, I'll be keeping the OEM setup on my bike thanks.

 

Brian H.

 

I would have to agree. If any thing I would maybe consider adding a crank case breather filter inside the air cleaner like the early fords and gms used to use and just change it as it got dirty.

[GeorgeS]

Well, its not legal in Calif. Thats for sure.

 

Yes, probabley better not to have the fumes going into the Intake, we all know that.

 

But it would also be better to figure out some way to draw the fumes from the crank case. I guess the old method of running a tube, down below the engine, useing air flow to creat a suction. That would theoretically work, but again, with current laws concerning polution, its not legal.

 

I know, we don't care.

 

Oh well, Kind of like the Warning light on my son's car. For a Vaccume in the fuel tank vent system. ( carpped out ) Check engine light on !! going to cost him about $1300 to get fuel tanks, pulled out, and new parts installed, before he can get the car re-licenced .

 

Enviro, wacko's strike again--- $$$$$$$

Edited February 20, 2009 by GeorgeS

[SilvrT]

As I understand things, the OEM crank case vent tubes go to the air box so that the vacuum created by the combustion air flow, will draw combustible gasses out of the crank case and into the combustion stream.

 

With your new setup, you have ambient air pressure inside and outside the crank case which won't vent the combustibles.

 

I don't like the looks of it, I'll be keeping the OEM setup on my bike thanks.

 

Brian H.

 

What did we do way back in the old days? Seems I recall the crank case was vented thru a filtered cap on the oil filler tube and each oil change, we washed that filtered cap with varsol and away we went. the whole idea of venting back to the intake is to burn off the gasses soas to reduce pollution isn't it?

[Condor]

At the end of the riding season last year, I bit the bullet and Installed a K&N Air Filter. Since the weather has been so bad here, (snowing again today, 3 ins. by morning) I have had an extended amount of time to do all of the things to my 87'VR that I would never do during the riding season. I removed the Air Box Cover and to my surprise there was a BIG messy oily spot on my brand new filter where the Crank Case Vent Tube enters the Air Box. I was not happy. Well the old 87'VR has 75,000 miles on it now and I figured that there is probably going to be some blow by. I remembered that on my 86' V65 Magna, before I rebuilt the engine I had the same problem and added a Crank Case Vent Filter and disconnected the Crank Case Vent Tube from The Air Box. So, I did the same thing on the 87'VR. The pics below show the plumbing that I removed, How I plugged the two holes in the Air Box, The New Vent Filter, and the final result. Any Questions, Feel free.

Earl

 

That's a lot better way to handle that vent hose Earl. I don't know about you but my hands are so big that getting in there to get that D@mn hose reconnected after R&Ring the carbs is a PITA. Keep up the tinkering... You're doing good.

[5bikes]

The suggestion was to just keep the oil level = or

Still got oil in the air box but better.

Really do not want to vent blowby to the air.

If we all had to directly breath our own pollution would we do it?

[Condor]

Well, its not legal in Calif. Thats for sure.

 

Yes, probabley better not to have the fumes going into the Intake, we all know that.

 

But it would also be better to figure out some way to draw the fumes from the crank case. I guess the old method of running a tube, down below the engine, useing air flow to creat a suction. That would theoretically work, but again, with current laws concerning polution, its not legal.

 

I know, we don't care.

 

Oh well, Kind of like the Warning light on my son's car. For a Vaccume in the fuel tank vent system. ( carpped out ) Check engine light on !! going to cost him about $1300 to get fuel tanks, pulled out, and new parts installed, before he can get the car re-licenced .

 

Envro, wacko's strike again--- $$$$$$$

 

There's always be a bit of blow-by that'll come out of the crankcase naturally without having to suck it out. All that hose does is take the blow-by fumes and run them back through the engine and burn them. In days of yore, engines with the old breather pipes did just fine, and I don't think I've ever heard of an engine going balistic on one of the old open crank pre-c.a.r.b. engines due to impurities. The recovery E.G.R. valve was the first attempt to get rid of those mosquito abatement fumes from old worn out engines. And I have several california bikes that quilaify for later EPA gas recovery canisters. All the canisters all gone. Removed by the first owners. So I don't see any problem letting the engine run with neutral atmospheric pressure, and I guess if the powers to be start checking for smog compliance, I can always put the hose back on.

And yep, I just spent $1300 bucks getting a couple of sensors replaced before I could get the suburban registered the last time around. I hate C.A.R.B......

[GeorgeS]

Yup: thats $1300 bucks that my son could have used to buy food for the kids!

[Squeeze]

Yup: thats $1300 bucks that my son could have used to buy food for the kids!

 

But George .... what the Food worth if your Son and the Kids can't breath ??

 

 

Sorry, i couldn't resist.

 

On the serious Side, this MOD may give you some extra Horses, because the mostly the Pump Effekt of the Pistons make up Oil in Engine Breather. If you allow the Engine to "breath" better, be it by opening up the Breather Path and/or keep the Oil Level on the low Side, it produces extra hp by reducing the Pump Loss.

[5bikes]

Checked my crankcase breather hose and it's still leaking oil into the air box and onto the multi-purpose chamber between the cylinders then all over the lower engine. I'm 1/2 way down on oil in sight glass.

So I disconnected the front drain hose I "T'ed" into the crankcase vent tube as Yamaha has suggested. Went back to draining the oil on the ground as Yamaha had it. (1984) I may add a small collecting reservoir later.

Inside the air box I added a T at the crankcase vent outlet and ran hoses to the top of the rubber air intakes. Oil/fumes have got to return to the engine now. 1 drop? every 10-20 miles? won't hurt anything.

I leak much more than I burn.

I'm going to lick this problem...

[Ivan]

The recovery E.G.R. valve was the first attempt to get rid of those mosquito abatement fumes from old worn out engines.

 

 

EGR valves is an Exhaust Gas Recirculation valve. The purpose of it is to mix a bit of the exhaust into the intake charge, lowering combustion temperatures, thus reducing NOx emissions.

 

What you are referring to, in actuality, is the PCV, or Positive Crankcase Ventilation set up. This pulls a vacuum on the crankcase, reducing blowby gasses, which are highly acidic in nature and cause the oil to degrade very fast. PCV had the side benefit of reburning those gasses, but, to my knowledge doesn't affect emissions in any significant way.

 

To the other guys that think there has to be a vacuum on the crankcase, that is inaccurate. The crankcase will build pressure, if sealed perfectly. The blowby on the cylinders needs a place to escape, and a vent is all it needs. Like stated above, a vacuum helps control these gasses and keeps the oil healthy longer, but is not necessary to the operation of the engine.

 

To the original poster, I have a very similar setup on my XS. That filter will get oily and smoke when you are at a stop. The combustion gasses will vent ok, though. It has never bothered me, but you will get oily residue around it.

[Squeeze]

You could shop around at the Vmax Sites, there should be a milled/turned Oil Filler Cap where y Hose can be conneted. Route the Hose upwards and then feed it back into the Oil Filler. This Idea is from Dyno Stage7 Kit.

[Dragonslayer]

I liked the mod because it illiminated the pain in the ARSE task of reconnecting the bannana/ twinkie hose whenever you had to remove the breather box. I'm still digesting the technical effects of the mod.

[skydoc_17]

Hey Bob,

Could you tell me how often you need to clean your vent filter? Is this something you do with every oil change or is it an "as needed" kinda thing.

Thanks,

Earl

[KIC]

Earl,

 

Need Update:

 

Did you keep your mod this way ? I have a similar set up on my 89, but it is on a longer hose that is "kinked" coming out of the crank case. I also just found that the plug at the bottom of the air box is shot and leaking air. Trying to decide if I want to return to original design or modify the modification.

[KIC]

Never mind. I answered my own question. I removed the little after market filter and replaced everything back to normal configuration with the T-fitting upgrade. Got it all put together and I feel and hear a BIG difference in the engine. Took it for a short ride and it felt smoother. I will be interested in seeing if it improves the gas mileage.

 

I will also have to see if it gets rid if the oil smell after being ridden and parked in the garage.

Edited April 22, 2012 by KIC

[yamtom]

Hi All,

When I got my venture, it had a burping sound coming from the air filter area. Earl and others told me to do the fix re oil levels, and putting that small breather in in place of the lines to the air filter.

After some thought, I decided I really didnt want miniature oil droplets to be deposited around the center of the engine area from a direct vent from the crankcase, so I put a new line in, and ran it to the rear of the bike directly venting it to the atmosphere. Running that big line back thru the bits of the bike, took a bit of time to do right.

My problem with the burping sound stopped, no oil mess near the carbs, and a little bit of drippage at the rear opening of the new line, especially when I run it hard, eighty or more mph. Happy happy, but I have to get one of those tiny filters to put on the end of that line at the rear of the bike.

[KIC]

Hi All,

When I got my venture, it had a burping sound coming from the air filter area. Earl and others told me to do the fix re oil levels, and putting that small breather in in place of the lines to the air filter.

After some thought, I decided I really didnt want miniature oil droplets to be deposited around the center of the engine area from a direct vent from the crankcase, so I put a new line in, and ran it to the rear of the bike directly venting it to the atmosphere. Running that big line back thru the bits of the bike, took a bit of time to do right.

My problem with the burping sound stopped, no oil mess near the carbs, and a little bit of drippage at the rear opening of the new line, especially when I run it hard, eighty or more mph. Happy happy, but I have to get one of those tiny filters to put on the end of that line at the rear of the bike.

 

 

Did you plug both air box openings underneath ? My big one was plugged but the rubber cap was rotted and cracked and the little one wasn't plugged. I know these air boxes are touchy as to the air flow and leaks.

[dacheedah]

I have a question, why not add a nipple to the filter and reconnect the vent?

[KIC]

I thought about that, but the vent was "misting" oil around the area of the vent. Also, I feel, after riding it some more this morning, that the it seems to run smoother, and just overall better with everything hooked up the way it was originally. This morning it fired right up with no choke. Yesterday, it needed a little choke and warming.

 

 

Just might be a personal choice. It could also have to do with making sure the air box is completely sealed and the crank case vent hose is not kinked. Mine obviously had several issues.

 

Unless you run the vent hose somewhere else to hook up the breather, or mount it directly on top of the breather vent outlet, there isn't a lot of room for the breather. This is why my vent hose was kinked.