Needing Air

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Combat crank case breather.

Teardown of my Combat engine prompted a review of my current breather system. This utilises a 4-reed one-way valve after the LH case mounted breather tower to positively evacuate air and oil away from the crank cases. A catch can then separates air for venting and oil for return to the oil tank using engine vacuum.

My improvement removes the 4-reed one-way valve and better utilises the breather tower to create a one way valve at the crank case exit. Calculation of breather tower ingress, seating and egress ports shows no restriction to maximum air and/or oil flow. Resistance to flow within my improved system is 13g and provided by a single 9/16" steel ball seated within the tower body. Additionally, a stainless steel ball or two balls in the tower may be used to modify resistance, if desired.
One of two convex steel mesh discs was removed (from the breather tower body) but the cap disc is retained to prevent the ball from potentially seating into the cap. The cap mesh has been magnetised to further enhance removal of metallic swarf from the system. Magnetising the steel ball was considered but this may compromise the ball's seating ability if it was contaminated with swarf.

To verify calculations, the dimensions are (mm):
Inlet ID: 18.5
Seat ID: 12.25
Body ID: 19.1
Outlet ID: 12.8
Ball OD: 14.28
Weight: 13 gram

The 9/16" steel ball cost AUD$1.00.

:D Trolls please note: I have no financial or any other interest in the steel ball manufacturing and distribution industries and provide this information gratis to the Norton Commando (Combat engined and other) motorcycle owners of Earth and beyond - May the Fourth be with you all! :D
Ta.
 
Interesting approach. I'm assuming the ball bearing is functioning as a one way valve.
Do you think the mass of the ball bearing will limit its ability to accurately track the pressure cycle of the engine?

Stephen Hill
 
Combat crank case breather.

Stephen Hill said:
Interesting approach. I'm assuming the ball bearing is functioning as a one way valve.
Do you think the mass of the ball bearing will limit its ability to accurately track the pressure cycle of the engine?

Stephen Hill

No I don't. :D
Zero or minimised positive pressure rather than a negative pressure in my cases is my desire.
Ta.
 
Have you tread it yet Needing?
It does look like a very nice and simple idea.
However, I visualise that at high revs, the ball will be bouncing round so much as to be somewhat less effective as a seal, hence my question re have you tried it yet.
Please do keep us posted.
 
Combat crank case breather.

Hi Fast Eddie.
Bores honed.
Waiting on rings and nuts to arrive.
Trials next week.
Update to follow.
Ta.
 
needing said:
Zero or minimised positive pressure rather than a negative pressure in my cases is my desire.
Ta.

I have recently modified my 750 with a timing chest breather modification. I realize that it's more along the lines of your modification, in that I won't get as good a vacuum as crankcase mounted reed valve application. I'm ok without inducing a greater vacuum because all I really wanted to do was eliminate minor oil leaks. I wasn't looking for any sort of hp gain...

What is the reasoning behind having less crankcase vacuum? Do you think there's a downside to drawing a greater crankcase vacuum?
 
Sheeze if this was a re-hash of the normal-recently popular flapper valves Needing would not of made peep. There are other effective ways to lower pressure enough not to leak that do not involve any valves as all and Kelly George and hobot are 2 of those by expanding crank case volume ported to TS case and long tube paths that let plenty pressure waves out but stifle return till next puff over comes it till reaching equilibrium of no flow in vent system but almost undetectable blow by excess that does not even distrub cig smoke held at exit to air. I am pleased needing has eliminated some gizmos in his system and should work fine even if not actually going below ambient. I chuckle at the beaming claims of flapper valves going a few lb below ambient for a few more top end hp but if a little is good then why no mimic Peel active sucker to really move vacuum needle enough to leave a hickey. Both Needing and me will get a bit added benefit from drawing in some fresh air through head to help carry out moisture and corrosive gases for rest of the world to share our successes outside the box of rest of Commandoom.
 
I re read it, its still in the theory stage :D.
My BMW race race bike has the reed valve that work fine in a road bike, however at engine speeds above 6500 to the 8000 redline do get a bit of oil in the catch bottle.
 
AMAL MK1 throttle slide.

Today's thought while waiting for parts to arrive.
Coldstart chokes are redundant on my bike so I thought I would block them off.
Cutaway angle is maintained and airflow looks to be better channelled across the spray nozzle.
Feedback on tuning trials & field trials to follow.
Ta.

No commercial affiliation with any carburettor companies except as a customer.
 
Looks like great minds think alike evolving UFO device twice in different species of crabs. Add a plate about 1/3 the way up bottom behind slide to complete the good idea. The V shape shown might also act as vortex generator on the short side of port bend so may get extra good response results.

Needing Air

Needing Air
 
AMAL MK1 throttle slide.

Excellent hobot.
I was prepared to defend my mockup as 'it made the throttle slide look pretty' - until proven to be practically 'tried and true' compared to theory. :D :D <-
Ta.
 
My buddy Wes with a 71 was sent a UFO for his Miki 34 carb and it gave a distinct boost from off idle on and bet yours does too. Btw I liked your computer graphics skill on the breather plumbing. Realize this forum has a lot of wantabe Harley types, ie: must fit within certain common styles and device upgrades or just do not fit in well.
Might consider knocking the spray tube down some for more streamling &or notching it too as the better flow should suck gas up quicker.

With a restless mind like yours I hope to disturb your peace of mind coming up with a system that handles oil and blow by pressure flows with active case evacuation and can function vertically on front or rear tire yet not leak much out upside down awhile in ravine crashes and weigh less take up less space than factory. With an air tank somehow on board could rig up a shot of pressure into bowls for a type of accelerator pump.
 
Combat crank case breather.

Bench testing show that the ball unseats at 70° included angle.
Ta.
 
AMAL MK1 throttle slide.

hobot said:
...With an air tank somehow on board could rig up a shot of pressure into bowls for a type of accelerator pump...
My first thought would be to insert a valve in the float bowl and then use the new fuel circuit to inject a metered volume of fuel to the main jet flow. How to trigger this and close the air intake effectively? I do not know just yet.
Ta.
 
hehehe great mind - reminds me of Peel's snorkle cork ball device that would float ball in a clear tube any time more fumes venting than still or reversing. I'm a bit slow to comprehend your ball vlave location or function and if the angle measured concerns cornering or what? Still Pin Ball Wizard flashbacks is neat sensation seeing that steel ball in a cage, which is polite'r than saying Pachinko. I resolved to go no brainer on Trixie Combat but for wise move to rear drain and removing the baffle in front of factory main hi speed windage oil return path straight into tank. Trixie got swarf in front passage I can't get out of cool contracted cases and does drain fine no weeps up to 3500ish/65mphish but beyond makes more and more mess. A screen before oil pump like comnoz is good preventive in case of part failure pieces but so rare its like ridding risks denial, by far mostly comes true or who'd be left to carry on the crazyiness. A real Combat simply can't wet sump much once running at any rpm through it becomes an elastic cartoon character at seams when 2S cam resonations kick in like a 3rd piston to me - but I've not the hard heart to press plain oleTrixie like my slut Peel put up with.
 
hehehe great mind - reminds me of Peel's snorkle cork ball device that would float ball in a clear tube any time more fumes venting than still or reversing. I'm a bit slow to comprehend your ball vlave location or function and if the angle measured concerns cornering or what? Still Pin Ball Wizard flashbacks is neat sensation seeing that steel ball in a cage, which is polite'r than saying Pachinko. I resolved to go no brainer on Trixie Combat but for wise move to rear drain and removing the baffle in front of factory main hi speed windage oil return path straight into tank. Trixie got swarf in front passage I can't get out of cool contracted cases and does drain fine no weeps up to 3500ish/65mphish but beyond makes more and more mess. A screen before oil pump like comnoz is good preventive in case of part failure pieces but so rare its like ridding risks denial, by far mostly comes true or who'd be left to carry on the crazyiness. A real Combat simply can't wet sump much once running at any rpm through it becomes an elastic cartoon character at seams when 2S cam resonations kick in like a 3rd piston to me - but I've not the hard heart to press plain oleTrixie like my slut Peel put up with.
 
Btw Peel with big holes in TS case and Combat breather baffle moved behind TS case and a Dreer supplied Krank PCV up by oil tank stayed so oil dry even with freq mid red line sprints to piss off moderns, her SS fasteners stayed nice but the steed washers and suds rusted where ya could see but not remove w/o undoing them. Same with unmodified Trixie Combat - until carb boots both cracked w/o knowing to suck in THE Gravel Grit so blow by blew sealing. i tried clear coat on fasteners and it lasted a couple seasons before heat removed it and rust patina showed up again.
 
Hardened steel weathering washers.

Hi hobot.
Hardened washers that are coated (up to a Standard) to withstand outdoor structural enviroments can be bought from fastener suppliers. http://www.astm.org/Standards/F436.htm
You will need to specify your requirements for atmospheric corrosion resistance.
Ta.


No commercial interest in fastener suppliers! I am just a customer.

Edit: Oops, thought hobot had asked about rusting washers.
 
Appreciate the washer pointer but Peel is sealed up and Trixie only gets Norton numbered items. Will try spray with Strongarm penetrate restorer oil in between power washing dust, muds bugs and blood off to stop in populated area.

Here rest your pressurized mind on these innovations, some claimed self charging pressurizing multi stages.
Needing Air

http://www.douglas-self.com/MUSEUM/LOCO ... irloco.htm
 
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