Engine Crankcase Breather

[Bob Kelly III]

BTW... a PVC valve for a car is a cheap reliable check valve just go pick one off the parts store shelf that looks to be the right diameter !
...... I guess I'll be putting one on my bike too if ...Grizld1 is right !
thanks for the Correction Griz.... LOL
Bob.........

 

[Paul75]

mine is going to be a very low miles bike so I'm just going to run the hoses out the back of the engine.

I'm going to do exactly the same. Very low miles bike here too. Going to run 2 short pieces of hose out of the engine, and above the filters.....job done!

 

[Bob Kelly III]

As Griz Mentioned they will make a mess on extended hard runs...... I amagen... so use longer hose and put the vent under neeth the battery area that way they won't make a mess of everything up under the seat..... just a thought !
I had a bike with no breather hose on it at all for a whort while ...a W1 650 a fast trip to town and back left my legs crotch and back of the bike covered in oil..... I discovered it was extinuating curcumstances ,....as the rings on one piston were stick to the piston.... I robbed a breather hose from one of the junk bikes on the Ranch and put it on there and fixed the rings.... it never did that again.....
...
Bob....

 

[Paul75]

OK will use longer tubes Bob, in-fact I'll use the new copy originals I bought, (wire sprung type), I'll just route them downwards.

 

[Bob Kelly III]

Good thinkin Paul <GRIN> its your butt on this thing keep it as safe as possable leave nothing to error or that error will come back and bite you !
remember you can't see the rear tire as your riding and can't tell if it's covered in oil or not the first turn will tell you for sure if it is though !!!!!
i have seen 4 guys go down hard because of blowing oil out on the rear tire in my life..... there is no keeping the bike up ! the last guy was a seasoned flat tracker and he flat tracked it into the ditch with a ka-thump.the impact bucked him off and he landed hard on a bunch of bolders...he had to buy a new helmit after that because it was cracked from the impact.... he was a tough Kid and it didn't even phase him LOL.
I wish you all the luck in the world of getting that beast up and running
Bob...........

 

[mrtwowheel]

Just for fun those hoses could be routed to barbs mounted on the exhausts about 3"-4" from the cylinder head to leave a trail of smoke. I always wanted to do that with transmission fluid, just to be annoying.

Scott

 

[5twins]

PCV valves are no good for this application. They have a small ball bearing in them and it can't respond/move fast enough for the engine pulses. The power brake check valve is a flapper valve which makes it more suitable for this application. They are cheap, fit perfectly into the stock hose, and have the proper 90° orientation needed. Poised over your pods, any oil mist or drips that do come out will just get recycled through the carbs, pretty much just like the original set-up. The outlets on mine are damp with oil but I've never seen them drip .....

I started out with my hoses run to a "T" then down to a K&N breather filter. After running it a while, that filter was all wet with oil. I never saw it dripping but it was very wet looking. The power brake check valve set-up is much better in my experience.

 

[Doug79]

I'm curious, in an automotive application, the PCV valve goes into a valve cover and is plumed into the air cleaner which will create a mild vacuum to remove crankcase vapors. In the other valve cover, there is a regular breather which allows filtered air into the crankcase to replace the air removed thru the PCV. If you are plumbing both hoses into a PCV valve, how are you getting fresh air into the crankcase to replace what was removed? Even in the old, pre PCV, days when there were road tubes, the oil fill cap was a breather.

 

[5twins]

You don't have an open source of air feeding back into the crankcase. You actually create a little bit of a vacuum in there, but that's supposed to be a good thing. It can reduce or stop minor oil leaks and the motor is supposed to produce a bit more power like this. I can't say I notice that though. But, I also doubt the flapper valves do a 100% seal, so a little air probably does get sucked back past them.

 

[mrtwowheel]

Some great responces here and some great explanations of what some members are doing about this. Vauge to me is how the tube is oriented with the foam pods, I take it they are just allowed to drip on the outside of the foam?

Scott

 

[5twins]

Yes, but like I said, they don't really drip at all. But, if some oil did happen to come out, it won't hurt the pod, it's coated with oil to begin with.

 

[Paul75]

5twins, this is great, it's more what I was thinking about in the first place, one problem though, I can't quite see from your first image how it is fitting together, the image is a little dark, you wouldn't have another image which shows the set-up a little clearer would you?

 

[5twins]

Here's an older shot from when I still had K&Ns. Not much to see really. Just cut the hose length so that it ends about midway over the pod and stick the breather valve in it .....

If it won't stay over the pod on it's own, zip tie it to the side cover hanger tab. On mine, this side stayed perfect but I had to use the zip tie on the other side.

 

[nj1639]

Well there ya go, dual outlet breather with the brake booster valve setting onto the filter.

 

[mrtwowheel]

Ah, the 90* check valve. Even if routing a hose down and lower than the frame, that 90* part would work well.

Scott

 

[Bob Kelly III]

Thank you 5Twins ! that helps a bunch ! I was un aware that the balls in the PVC valves weren't able to react fast enough ...so the reed type
powerbrake valve seams to be the answer ...Very smart ! THANKS !
.....
Bob..........

 

[Paul75]

This part is actually quite small huh! I was thinking it was much larger. Now....these are very hard to find in the UK.....is this it:

http://www.ebay.co.uk/itm/331727211343?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

 

[theDQG]

Glad I ran across this thread. I was just thinking about what to do with my breather tubes.

 

[theDQG]

https://www.amazon.com/dp/B000CO973...targid=kwd-64545478248&ref=pd_sl_7py6grbwcy_b

 

[nj1639]

Yep, the generic HELP! Dorman, available at all of your friendly auto supply stores.
The UK eBay Jeep item should work as well.