NEW reed valve breather fits all Commandos? (2017)

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

gtsun

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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.
 
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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.
 
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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....
 
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BrianK said:
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.
 
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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.
 
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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.
 
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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.
 
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Its canted up and angled back on mine and all the others I have seen on MK2a's, looks the same angle as the earlier picture of the breather fitted to a MK3. Earlier 850's may be different.


 
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thanks Kommando. So mine is in there right.

Getting it out is proving to be quite the challenge.
 
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Thanks Dave. That worked. Took a LOT of heat and a 4ish foot breaker bar and the little bugger fought every thread of the way. But it's out.

Now seeing what Jim meant by being held in only by sealer - the new one isn't bottoming out or taking any torque. The blue (this time - I am convinced there was red on there) is all that will be holding it in I guess.
 
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I found out (as LAB said) the breather is too tight against the original prestolite starter by about .100"
So I'm thinking it needs a bent threaded tube similar to the cut & welded tube on the 750 rotary valve breather so it will clear the early starter. Is it worth adapting this breather to the prestolite starter - or are they all getting replaced with the shorter starter? If its worth it then I need someone to try the fit for me.

Brian - sounds like someone messed with you by using red loctite. Red loctite needs to be heated until it starts to smoke.
 
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I think so Jim.

Other than that, a pretty easy job. I had to loosen the oil pipe junction but didn't need to remove it, which made that easy (1/4" Whit). The jam nuts fit a 7/8" socket/wrench and the breather body took 5mm Allen wrench IIRC corretly.
 
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In case anyone wants to know how the thing works, I can confirm a pretty significant decrease in oil leakage. After a hard run it'll drop a single drop of oil, like clockwork. Formerly I'd get quite a bit more, maybe a teaspoon or two. So I'm pleased with it (now to address that drop....).
 
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I made a breather valve using a BMW twin reed valve. I made a housing that looks like two funnels pressed together. It works perfectly. Didn't have to modify anything, just cut the breather hose and install it. I'll see if I can upload a photo.
 

cliffa

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I made a breather valve using a BMW twin reed valve. I made a housing that looks like two funnels pressed together. It works perfectly. Didn't have to modify anything, just cut the breather hose and install it. I'll see if I can upload a photo.

Jackson5, I'd Love to see that.
 
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