What do people do with Breather Outputs With No Airbox?

rsylvstr · Full Member Joined: Aug 09, 2008 Posts: 65

5twins wrote:

Here's the one I used (well 2 actually) Power Brake Check valve part # 80190. You can't use a PCV valve because they have a ball bearing in them and it won't move fast enough at higher RPMs. Basically, the thing won't function.

can you just remove the T fitting and the two hoses and use one of these?
i just made another post in the Fuel section...i probably have it all screwed up. TIA

metalredneck · Full Member Joined: Aug 04, 2008 Posts: 308

I installed check valves
farm4.static.flickr.co...862a3d.jpg
& lowered my breathers today.
farm4.static.flickr.co...f977ba.jpg
Thanks for the info on the oil level, my stress level is better now.

BTW, for pics of the scoot in question, check out "El Noobo Canuckistan" in the newbie section. Safety glasses recommended. Shocked

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

Breather filters probably aren't needed now with the one-way check valves. It's not sucking anything in anymore, just puffing out.

metalredneck · Full Member Joined: Aug 04, 2008 Posts: 308

Yeah, but I bought 'em, and they won't fit my chain-saw, so there they are.

TeeCat

I'm putting mine on too, mainly to catch mist. All I need is some spare time!

p73ornstar · Full Member Joined: Jun 17, 2008 Posts: 54

The chainsaw? Joyce the Assault Raisin is pretty nice, make sure to compliment that brazen beauty!! And to be on topic, I will be doing this mod when I get mine put together. Sounds like a great idea to keep leaks down to a minimum.

MrMopar · Full Member Joined: May 06, 2008 Posts: 19

My '75 XS has the breather tube routed through a hole in the left side cover so that the oil mist keeps the chain lightly lubricated. Is this not a stock installation?

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

It might be a stock set-up on a model as old as yours. Back then, folks put regular oil on their chains. Today you can do much better with a specific chain lube. Unless you're doing a full 10 point resto, I'd change that.

Retiredgentleman

I had an 1976 XS500C and the breather hose went down and through a hole in the top of the left cover, directly above the chain.

xsjohn

Yea...in 76 things made sence.......those were the days.......now we have to spray all the crap every where and then clean it off after it slings.....

On my RT1 I cut a bit of a grove in the spacer that fits behind the sprocket so a bit of trans oil would leak out and sling on the chain....what a brainer I thought I was...easier to put a bit in the trans once in a while than to lube the chain.......

xsjohn

TeeCat

After having done this mod,I went on a test run of about 15 miles, and there didn't seem to be any additional oil spatters on my left pipe. Also, there were only one or two tiny drops below the bike when I parked it. I'll assess it some more, and maybe rig a tube and filter "bib" to catch oil droplets if it does not stop completely, for the time being.

TC

jdallen

Adding this brake check valve is on my "to do" list. Just wondering if you guys that've done this still think it's a good idea? currently I've got 2 long tubes hanging (and dripping) behind the engine.....

How do you get them to sit on top of your air pods? I think they'd just vibrate off.

TeeCat

jd, no need to worry about shortening the hoses. I just installed the valves on the ends, and then affixed two mini-cone filters (you can get them an your local auto parts store) to the small ends of the valves, and zipped them neatly to the frame with heavy duty ties. You can see the filters protruding slightly in the image below. They'll catch your misting/drooling, and allow breathing as well.

TC

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

I've been trying a load of different methods to sort this...and the long and the short of my exhaustive (!) findings are...

Straight in and out pipes with filters on the ends smell bad but dont cause leaks.

Incorrectly rated one way vavles meant for power brake servos that are available in the UK take to much presure to open and cause leakage.

However...Mikes breather with a few mods to attach it to a filter stops the leaks straight away, and minimises smells..as well..

Great product, shame it doesnt come attached to a nice little filter..

jdallen

I think I'll try it. I've read about it here as well as on some Norton and triumph sites. Mostly I'm just hoping it might stop a tiny amount of oil seepage I get at the front of the engine. I don't really notice a bad smell......of course I don't take baths though.

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Yeah..me thinks its what everyone needs for minor leaks and seapeges from seals and gaskets that should be OK...

jdallen

Do I detect a hint of sarcasm there? jake68, Didn't I read on an old thread that you had some problems b/c of a restrictor valve that didn't open and it blew some seals in the engine?

anyways, that's what I'm worried about, but a lot of ppl here in the U.S. are using that same check valve.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I've had the check valves installed all summer now and am quite happy with the results. I thought I might need to zip tie the hoses to something in order to keep the valve poised over the pod but it turned out to be unnecessary. The routing of the fuel lines pushes against and directs the breather hoses right where they need to go.

There has been no oil dripping and minimal misting so far. The ends of the valves are just slightly damp with oil. I contribute this to 2 things. First, I'm very careful to run the proper amount of oil. I set the level about half way between the low and high mark just as Yamaha recommends. Second, and I feel this is the most important thing, I have the factory rubber restrictor plugs in place in the ends of the breather nipples. Run without those and you will mist out more oil, regardless of the level.

jdallen

Right on. Is there any reason why I couldn't have my 2 breather tubes come to a T and then go to one check valve? I plan on having the tube long and the valve hanging kinda low, but 1 would be cleaner than 2.

I'll check for the factory rubber breather nipples.....

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Hey jdallen...

I did but those valves took much more pressure to open than the new one from Mikes.

yes I did have a problem with weaping seals and gaskets due to the removal of my airbox...

These engines and their seals / gaskets are generally are designed for the induction induced crankcase vacuum. Thats actually a positive vacuum generated by induction from what I can deduce from exhaustive emails with a reknown expert on crankcase breathing.

If you just have a straight through system you may get some leaks or seaps due to the fact that the pressure remains positive. Even though its very slight.

If you do have a very free flowing valve some negative pressure is possible without the aid of induction. Mikes valve is the most free flowing I've found to date..especially amongth those available in the UK at least.

This should stop minor leaks.

If you have a system without a valve you will get positive pressure as far as I can tell. You cant avoid it. You may get close to be OK by taking out all restriction but you will probably loose oil without splash plates etc.

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

I'd like to think that by placing my valves over the pods, I'm adding some induction draw just like the original set-up to the airbox. Whether that makes a whole lot of difference, I really don't know. 650s from '75 and earlier just vented the breather hoses to atmosphere.

I have been giving some thought to how long the hoses to the valves should be. I don't think the motor generates huge amounts of crankcase pressure. I think XS John measured it once and found only a few pounds. Place the valves at the end of a couple feet of hose and maybe that small amount of pressure might dissipate before it reaches the valve. There might not even be enough pressure left to operate the valve. Mine are on about 6" of hose, slightly shorter than the original that ran to the airbox.

xsjohn

Personally I like the stock air box but maybe you guys that use pods could bore a small hole and insert a piece of tube into the pod....like arrow shaft or something.....and epoxy it well in the filter material........then you could get back to what it was to begin with .......with all the other contraptions added too.....

xsjohn

xsleo

if you are useing pods with metal end caps, drill a hole in the center off the end cap install a hose barb in each. hook to gether with a hose with a tee in the middle. run the breather hose from engine to check valve to the tee. any excess oil mist will be drawn into the engine and burned. no mess on the bike.

Jake68 · 650Rider Supporter Joined: Mar 23, 2007 Posts: 841

Put it this way...if my stock airbox and battery box tinware handnt been discusting and rusty..and knowing what I know now, it would still be in place!

I just wanted also to clarify, that none of the check valves I could find in the UK opened easily enough..they all proved too restrictive...

It seems that the ones available even from wrecking yards in the US are very free flowing.....

Its just not fair Smile

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