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XR200 XL185 style oem Honda early breather-seperator..

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I'm running an XR185 engine in my little 1981' Honda CB125S on the street and this bike uses the exact same Early style breather-separator as the XL185(#17361-419-670 main breather body)which screws onto the bottom of the airbox with 3) small screws on my bike and has a tube which comes out of the top of it inside the airbox that feeds directly into the airfilter endcap,which blows oil mist back into the engine.The trap assembly used to have a small,tapered round baffle(it looked a little like a cone with slits in it) and foam filter inside of it,but it clogged-up so I removed those 2 parts:should I have modified those 2) parts somehow to allow them to separate the oil/PCV junk better? I like how the hose sticks-out the side under the bike and just empty it occasionally.. I realize a standard,aftermarket 'fix' would be just purchase a small breather filter and stick it onto the end of the breather hose:those things get really gunky and if I could keep it inside the airbox somehow similar to the OEM set-up,I'd prefer that.I would like to install an XR200 airbox but there isn't enough room on this little street bike:the airbox with battery mount are just the right size.I just want to improve this breather/separator and make it the best I can so it separates And catches the junk,and I empty it later;Plus I want it to scavenge the pressure out of the engine cases so I won't start blowing seals/gaskets,etc. I appreciate any good ideas you might have. Bill 😉

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I've not owned a XL but it seems to me an easy choice would be to use the XR style of breather, but with mods, and plug the XL holes in the air box.  I mod my XR breathers by plugging the road draft end to prevent water entry on water crossings but for street use you could leave the road draft tube because if sealed it does require periodic cleaning.  I add a K&N filter to the top open end the keep dust out of the engine, here is a pic of mine after a very dusty ride. 

1451152775_XRCrankcasefilter.JPG.79ac4d49c55cc7e9cded3fe65c5495a8.JPG

And a pic of the sealed off lower tube:

1485642315_XRCrankcaseVentBrakeReservoir.JPG.27008dfb8ce939cd2d9a915809cbfee7.JPG

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Posted (edited)

Hello Chuck,I see how you installed that little PCV filter up-high and then sealed the lower elbow? The system I have uses the same PCV trap on my 81' CB125S as the XL185S uses in the front of it's airbox,only my OEM trap is mounted to the bottom of the CB125S smaller steel airbox using the main 3) screws that hold it together and has a rubber hose connecting the top of it inside the airbox(hose attached to an elbow) directly onto the end-cap of my OEM air filter assm(to possibly draw suction to give negative pressure inside the crankcases?)and I sometimes wonder if some of the PCV oil-mist and other stuff is getting drawn into the firing zone of the engine? I see the logic of using vacuum to keep pressure inside the cases from building-up and blowing seals,etc.The stock parts inside the breather/separator include the 2 part numbers i mentioned at the beginning of this thread:I took them both out.. I was hoping it would allow the breather/separator to scavenge better because the little foam filter inside the OEM Honda breather/separator(XL185 is exactly the same part number as my 81' CB125S)seemed to be getting clogged.I like the OEM system on my bike better than the small K&N style PCV filter because it stays clean;the drain tube is plugged at the end near the lower part of the low street muffler at the bottom & when it fills-up,I remove the spring clip,plug & empty the rubber drain hose of it's 'fluids' into a drain pan,then re-install the plug and clip;simple enough for me to do.There are lot's of early 80's Honda street bikes which use this same breather system/parts.I'm asking if there's a way to improve the OEM XL185S/81' CB125S breather/separator to allow it to work at maximum efficiency;possibly install some sort of fine mesh screen,etc. inside the breather/separator so I can limit the amount of oil mist which would otherwise be sucked-upward thru the tube into my filter assm. but would rather allow it to head-down the other way by gravity toward the rubber tube/drain tube 'reservoir'  ?   🙂  thanks,Bill

Edited by grcamna5

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