Welcome to the Access Norton Forum. Login as a VIP member to remove the advertising banners.


NEW reed valve breather fits all Commandos?

Classic Norton Commando Motorcycles.

Re: NEW reed valve breather fits all Commandos?

Postby xbacksideslider » Thu Apr 20, 2017 12:26 pm

That's a beautiful piece of engineering, especially since it can be used on multiple models.
John Laing
1973 750 #220000
1986 GSXR 1100
2008 CBR 1000
1986 Shelby GLHS #463

xbacksideslider
Posts: 1233
Joined: Thu Aug 19, 2010 4:50 pm
Location: Southern California

Re: NEW reed valve breather fits all Commandos?

Postby jseng1 » Thu Apr 20, 2017 12:39 pm

pantah_good wrote:Thanks Jim, it is a handsome part. The photo of the Combat / Maney version, is that shown mounted on a Maney case?


Yes. Its a Maney case.

Here's a vid of the blowby diff between a reed and no reed.

phpBB [video]
User avatar

jseng1
Posts: 1495
Joined: Thu Nov 26, 2009 11:50 pm

Re: NEW reed valve breather fits all Commandos?

Postby texasSlick » Thu Apr 20, 2017 2:42 pm

jseng1 wrote:Slick - I started out with the timed Atlas breather. I got rid of it and use the reed valve. The timed breather does not work the same for all RPM when under load but the reed does. The air has to pulsate and it compresses. When the RPM changes - those pulsations do not always match the timed opening of the disc. We learned this in racing and discarded the timed discs. The reed doesn't care about timing - it just senses the pulsation. The four 1/8" holes in the cam are enough because once the positive air is pumped out there isn't much pulsating air movement going on. There are others who have tested and compared the reed to the timed breather - maybe they could chime in here.



Jim:

I can accept your explanation of the phase difference between the timed disc and the actual pressure pulse.

The point I was trying to make in my previous post, is with the timed disc in place, the reed does not improve the negative pressure in the sump, according to my measurements. I can only defer to your experience with the timed disc removed.

It would be interesting if you can provide some pressure measurements with your new reed valve on your Atlas' timed port (you once posted your rotary disc is removed). If such data shows a substantial benefit, it is a pity a complete tear down is necessary to remove the rotary disc.

Slick
1963 Atlas (Original Owner)

The Second Law (of thermodynamics) rules.
User avatar
Access Norton VIP Paying Member
texasSlick
VIP MEMBER
Posts: 1708
Joined: Wed Jan 02, 2013 8:38 pm
Location: Bullard, TX

Re: NEW reed valve breather fits all Commandos?

Postby jseng1 » Thu Apr 20, 2017 4:06 pm

Xbacksidelsider

Thanks for the compliment. I put a lot of hours into the design to make it work.

Slick

I have not compared the diff between the reed valve with the timed disc and the reed valve without the timed disc. That's another test that needs to be done. There are some simple tests that anyone can duplicate.

Loosen the oil cap. Without the reed breather the cap will bounce well off the oil tank. With the reed breather it pretty much sits still. You can also see the amount of bubbles in the video above. Pressure tests will have to be very sensitive. Just immersing the hose into the oil changes everything. Never make this test with water because it can suck water into the motor when backing off the throttle without a reed valve.
User avatar

jseng1
Posts: 1495
Joined: Thu Nov 26, 2009 11:50 pm

Re: NEW reed valve breather fits all Commandos?

Postby jseng1 » Mon Jun 12, 2017 11:37 am

I just realized that you can use the easy to install version of the breather without taking apart your motor. Then later on when you rebuild the motor - you can move it to the lower rear sump area if you choose. You have to drill and tap some holes as shown in the tech section of my web page but all you need is two longer screws to bolt the breather to the case, a sump breather gasket and plugs for the timing case vents.

Image
Last edited by jseng1 on Fri Jul 14, 2017 12:50 pm, edited 2 times in total.
User avatar

jseng1
Posts: 1495
Joined: Thu Nov 26, 2009 11:50 pm

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Tue Jun 13, 2017 5:25 pm

Ran across this thread last night, hopped to Jim's website to order, and USPS tells me the part is already on its way to me - thanks Jim.

Haven't been out to the garage to look - does the old vent tube (850 Mk 1 - as I write this I'm having that oh-shit realization that Jim's site refers to Mk 2 and I don't know if there's a meaningful difference in this regard?) just screw out with a pair of vice grips or the like?

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby kommando » Wed Jun 14, 2017 2:48 am

Normal RH thread on the old 850 breather tube where its screws into the timing case rear.
User avatar

kommando
Posts: 2147
Joined: Sat May 07, 2005 10:24 am
Location: Scotland

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Wed Jun 14, 2017 6:49 am

Thanks Kommando.

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby gtsun » Thu Jun 15, 2017 8:22 am

My 850 has always been completely oil tight ever since I got it until about two years ago when it started seeping oil Around the front to head bolts. I pulled the head and sent it off to Comstock for a complete redo which of course came back stunningly beautiful (thanks Jim) but I've still had a little oil seepage at the front. So I just ordered one of your breathers and a few of the new fiber reinforced silicone gaskets which I think are a really great idea. I'm hoping this makes the beauty completely oil tight again. I'm one of those people that can't handle having oil dripping down the fins, it takes the joy out of it to me and I've always taken pride in not leaving oil puddles everywhere. Thanks for making great Norton parts you guys. Glenn T.S.
Access Norton VIP Paying Member
gtsun
VIP MEMBER
Posts: 1618
Joined: Mon Sep 21, 2009 12:58 am
Location: Fullerton, CA. USA.

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Thu Jun 15, 2017 6:03 pm

Mine's here! A nicely machined precision part, no surprise there I guess. Clear installation instructions - not sure even I can screw this up. But watch this space for my panicked queries when I get around to the job....!

Seriously, thanks Jim.

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Sat Jun 17, 2017 8:21 am

I warned you....

Holy cow, is that OEM breather tube welded in? 195#, I ain't Schwarzeneger but not weak. 6" vice grips on the tube and two hands/full force cranking on it to no avail. Looking for a pipe or the like for leverage but the angle intersects the oil tank. Hmmm....

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby jseng1 » Sat Jun 17, 2017 8:45 am

BrianK wrote:I warned you....

Holy cow, is that OEM breather tube welded in? 195#, I ain't Schwarzeneger but not weak. 6" vice grips on the tube and two hands/full force cranking on it to no avail. Looking for a pipe or the like for leverage but the angle intersects the oil tank. Hmmm....


Shouldn't be that tight. Its only held in with sealer. Use heat rather than muscle. Turn counterclockwise looking at end of tube. Never heard of this problem before.
User avatar

jseng1
Posts: 1495
Joined: Thu Nov 26, 2009 11:50 pm

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Sat Jun 17, 2017 8:51 am

Thanks Jim. Turning the right way (RH thread). Thought of heat but I'm trying to do in situ, and the float bowls of my carbs (35mm Keihin FCRs - physically long, vertically) are only a few inches away so I'm reluctant to bring in the torch...! Maybe a soldering iron. God knows, one of the (3?) prior owners may have used red loctite or the like.

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Sat Jun 17, 2017 10:52 am

Slipped a three foot hollow barbell bar over the end of the vice grip handle and cranked on it. No joy. I gotta think somebody used red loctite. PITA.

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

Re: NEW reed valve breather fits all Commandos?

Postby BrianK » Sun Jun 18, 2017 8:56 am

Dunno if this is relevant, but is that breather tube supposed to come straight out of the back of the timing case? Mine is canted a little up and significantly rearward.

BrianK
Posts: 1709
Joined: Thu Jun 14, 2007 5:31 pm
Location: Boston, MA USA

PreviousNext

Return to Norton Commando Classic Motorcycles

Who is online

Users browsing this forum: L.A.B. and 7 guests