OzVMX Forum

Clubroom => Tech Talk => Topic started by: John Orchard on December 28, 2014, 06:55:40 pm

Title: More engine & gearbox life ..... breather hose! READ THIS !
Post by: John Orchard on December 28, 2014, 06:55:40 pm
I've been amazed how quickly gearbox oil become dirty, after 40 years I realize that the breather hose vents down under the engine just the front of the rear wheel, possible the dirtiest area known to man!

So now I either fit an in-line fuel filter to the end of the hose, or put the end of the hose into a block of oiled, sponge foam, and place it in a less dirty part of the bike.  This is surely going to stop dust getting into the gearbox,  I reckon this would have to give 10 times better life to the internal components.

While stripping my modern RMZ450 one day, I found the engine breather hose vented to exactly the same place as above !!!!  What is Suzuki trying to do to owners of their bikes?!!!  A 4-stroke is going to breathing quite heavily in & out of that breather, sucking in a huge amount of dirt !!!!  My RMZ now runs a hi-flow fuel filter on the end of the hose, and breathes from under the tank, not down at the rear wheel.

Why the hell would anyone just bother cleaning airfilters when heaps of dirt gets in through vent hoses?
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: Tim754 on December 28, 2014, 07:11:03 pm
On my sidecar engines John, I have re routed the breather tubes to inside the air filter box, same as most cars ;)
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: Slakewell on December 28, 2014, 07:17:30 pm
If you vent to the airbox make sure water can not get in.
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: John Orchard on December 28, 2014, 09:17:30 pm
Venting the hose to the airbox aint going to help very much; how dirty does an airfilter get. The hose must have a filter attached for any real benefit.
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: jimson on December 28, 2014, 09:40:25 pm
Thanks for your input on this. I will look at all of my bikes & address the situation.jimson
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: Tim754 on December 28, 2014, 10:36:34 pm
Yes I have inline moisture filtering :-* Of course the outlet exits pre air filtering... all access points have oil and fuel proof grommet and silicon sealing, and all hose tubing is routed , guided and cable tied to avoid kinks,crushing and splits.

If your air filter is being covered in obvious oil residue or sludge from your engine/gearbox breather hose   umm   you may have a problem or three needing review there.....

If your air filter is just dirty...... :-X
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: OverTheHill on December 29, 2014, 06:51:24 am
can you connect it into the aircleaner so it breaths through the filter from within. Not sure it would matter [huffing & blowing], if you dropped it you may get some oil escaping but may only wet the filter a bit more. Not quite relevant but back in the RD400 days their air bleed to the needle jet [emulsion tube] was from a separate hoses plugged into the air filter element, breathing from within. No idea why they did that in those years. Anyway--clutch linings [someone said] can dis-colour the oil, me thinking two strokes but why not all, plus blow by on 4/ if she's getting a bit tired.
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: FourstrokeForever on December 29, 2014, 09:18:55 am
Yes, the clutch plates are the biggest factor in dirty engine oil. The pulses on a fourstroke as it breathes in and out are so fast that it is very unlikely that any "dirt" will get into the motor, unless the breather hose is so short that the dirt can get there in a hurry. Still, re routing to a higher place like under the tank or somewhere else high is a good idea. Even better with a filter at the end.
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: 211 on December 29, 2014, 09:59:01 am
on my Velocette i had as much crankase compression as combustion and couldnt keep a gasket in the thing so I vented the engine at the rocker box and used a Ford PCB? valve on the end of the vent line - motor ran better, lot less oil leaks. Im sure there are guys out there who know a lote more about this than me and I wonder if the modern engine vent is there for similar reasons?
211
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: FourstrokeForever on December 29, 2014, 10:12:22 am
It's a PCV valve Dave. And yes, venting the engine does help keep crank case pressure down. It's a well known fact the the better an engine breathes, the more free it will run. I had oil blow by on my Beezas until I also put breathers at the rocker boxes. No more oil leaks  ;D
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: KTM47 on December 29, 2014, 10:53:01 am
Would the little plastic one way valves that can be sometimes found in fuel tank breather hoses do the job?
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: alexbrown64 on December 29, 2014, 11:05:37 am
There must be something in using a Positive Crankcase Valve, as in the case of a car, if you have a blocked one, your car can run like shit, so i guess in certain cases, this could hold true for motorcycles as well.  You would think that the little piece that comes out of your case for the breather tube to attach to would be a 1 way valve.  Perhaps they were worried about these getting blocked all the time and creating running issues.  Could be a good little after market item here.
Cheers,
Alex
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: mick25 on December 30, 2014, 03:25:00 pm
I run a filter system on my breather hose , I got it from super cheap auto it has a foam filter and a stainless screen in it , I oil the filter like the air filter foam it works great but they don't sell them anymore.
A bit more on gear box life what I do.

On my TT500 it has magnets glued in the removable sump this picks up the slightest of metal paste from gear wear etc .

I also came up with a theory on new oil and whats in it being dark in colour and spotting foreign objects in it , there shouldn't be anything in it but oil  ??? .
 I use a funnel with a very fine stainless steel screen in it with a magnet in it to filter the new oil when I do oil changes etc.
might sound a bit paranoid but better safe than sorry.
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: PEZBerq on December 30, 2014, 06:03:16 pm
Mick
Filtering new lube and hydraulic oil from the suppliers drum or container is best practice in industry. There is a reason they often use black containers!
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: Rossvickicampbell on December 30, 2014, 06:38:25 pm
yeah - try gaining compliance with CAT 5 star for lubricants!!!
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: John Orchard on February 10, 2015, 03:47:54 pm
This is the filter I just fitted to the CR500 breather hose, got it from the local lawnmower shop, think it's from a brushcutter.  I'll let yoos know how dirty the oil gets when I change it next.

(http://i1093.photobucket.com/albums/i423/JohnnyRacer89/CR500%20gearbox%20breather%20filter_zps8t3jdz9v.jpg) (http://s1093.photobucket.com/user/JohnnyRacer89/media/CR500%20gearbox%20breather%20filter_zps8t3jdz9v.jpg.html)

Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: YZ250H on February 10, 2015, 04:04:58 pm
Nice one John.   Will be interesting to see what happens
Title: Re: More engine & gearbox life ..... breather hose! READ THIS !
Post by: MaxPower on February 17, 2015, 11:20:00 am
I stalled my wr450 in water that covered the bottom of the crank vent. I started my engine to get out and immediately checked the oil only to find a bunch of gray yuk. Had i gone about my day i woukd have had repair bills more than the bike was worth