Crankcase Breather

swooshdave · May 15, 2009

There have been some good topics on this.

This is very neat and tidy.

And the one Jean did. Gotta admire anyone who can mill using a lathe.

The idea I had was to use the whole intake assembly from a small bike (you'd just need to flip the reed valve over) and see if it would offer up to the crankcase.

This is from a Yamaha PW50. Retail prices are about $25 for the intake and $30 for the reed valve. SInce most (if not all) of the intakes will be 4 bolt it may just be a matter of finding an intake with the right hole pattern.

What I don't get is that CNW says on the 72 no modifications will need to be done to the crankcase but if this picture from Old Britts is correct the 72 only have a two bolt setup.

So I'm trying to do the math on the 4 into 2 thing. :?:

chris plant · May 15, 2009

hi swoosh,it could be that a square plate with threaded holes in each corner (and a big one in the center of course)is bolted to the cases using the 2 bolts first, then the square reed block is bolted to that ,just guessing tho

swooshdave · May 15, 2009

chris plant said:
hi swoosh,it could be that a square plate with threaded holes in each corner (and a big one in the center of course)is bolted to the cases using the 2 bolts first, then the square reed block is bolted to that ,just guessing tho

That's what I was going to guess too.

swooshdave · May 15, 2009

Here's the reed valve from a chainsaw. Two bolts. Don't know the dimensions.

Don't know if it would flow enough.

Jeandr · May 15, 2009

Here is my blatant copy of CNW's breather system. The reed valve is off e-bay ($10 + shipping) and it is used in pocket bikes with two stroke engines. Unfortunately, my tools are not big enough and I had to have the crankcase machined by a real machinist ($110) I cut my own gaskets from material I had stuffed in the rafters in the basement. Cost comparaisons are about $150 Canadian $ for mine and $265 US +$140 US (shipping there and back) for CNW but I have to admit that CNW logo speaks quality and trickiness. Did I ever mention I am a cheapskate :lol:

Here is what must be done to plug up the holes in the RH case and the added hole to drain the timing chest.

The multiple arrows point to holes that have been blocked and the single one on the left points to the new drain hole (sorry for the french text). I plugged up the hole to the points wires because I am using an old timing cover with a tach drive gearbox on the end of the cam. The plugs can be found at engine rebuild shops, I used two 1/4" NPT (National Pipe Threads) plugs and three 1/8" NPT plugs. The old breather was plugged with an aluminum plug I turned, I think it's 9/16" or 5/8" x 20. A plate could be used or get a 3/8" NPT plug. Plugs are 25¢ for the small ones and 50¢ for the big ones.

Jean

swooshdave · May 15, 2009

Jeandr said:
Did I ever mention I am a cheapskate

After seeing all the pictures of your bike no one is ever going to accuse you of being a cheapskate. More like ingenious or resourceful, but not cheap.

chris plant · May 16, 2009

hi jean,will there be enough oil in the timing chest with a drain hole that low in the case ,i would have left the one just above the pump on the left that drains to the rear of the crankcase

Jeandr · May 16, 2009

That's the way CNW does it as per Jim Comstock's instructions. I think it should be OK

Jean

marinatlas · May 17, 2009

Hi Jean, good job and interesting way of breathing , but in that particular case was it necessary to remove the oil baffle inside the case and if 750 post 200.000 case to plug the front scavenging oil hole (in fact all the "old brit's mods") ?? working on 850 and 750 cases is different as they are not exactly the same ..........as I am on the way to rebuilt one 750 engine for a friend , and have allready remove/mill this oil baffle , but not yet plug the small hole neither drill the timing case, want to fit the XS performance reed valve (as on my 850), so wonder as well if I can use in a more easy way the actual 750 breather "pick up " and just put in this XS reed valve in , but adding your modifications ( plugging all extra holes in the timing case ....(could PM you in french, makes life easier as well !!!! )

cNw · May 18, 2009

Hi,

Couple of reasons for this post.

First I just feel like I have to say something about the copying of the valve we make. I certainly understand that nobody can protect themsleves from people copying product (except with copyright of course), especially if the parts have been proven to work. What does disturb me is that somebody is comparing prices the way they do. They are proud to let everyone know that they can take someones ideas, copy it, and do it so much cheaper. What these people fail to consider is that it takes a whole lot of money to develop these parts. The price difference is certainly not because there is a Logo machined into the valve body.

-Number one we have a whole lot of time, years actually, for Jim Comstock to fine tune and make sense of how this valve need to be made to work as well as it does.
-We have developed CNC programs for 3 different valve bodies and 1 adaptor plate. MKIII, standard and -72.
-We have to make vaccum fixtures for those above parts.
-We have to machine enough of those above parts to make sense of the setup charges and try to bury some of the initial costs to make sense out how much money we have invested in each part
-We had to design and make a fixture that works for all engine years that will allow us to make mill the mounting area on the cases.

If I told you what the above cost many would probably think we are a bit crazy for doing what we are doing. Heres the thing though. We like to develop and bring these kits and developments to the market so many can benefit from them....this is the American way to do business isnt it.. If after we put all this time and effort into all this and didnt make any money of the end products...well, we wouldnt be in business for long. There has been countless American companies that had to close their doors after some over seas companies copied their product and offered it for less. We are not a hobby business....we do this for a living and can hopefully do this for some time to come.

I know we are going to sell a lot of valves because they work very well and most individuals arent going to try to make their own. If some decided to make their own, that is fine to, as long as they dont go out there and brag how great they are for taking sombodies hard work and discounting it. Making us look like we are over charging because we have all of our startup costs that have to be paid for.

The second reason for the post is in regards to the question about the -72 installation of our breather. We have designed and are making an adaptor plate that first mounts to the cases and the valve fits onto it.

....why dont you ask Jean to make you a copy of one. It will be a whole lot cheaper than buying it from us !

Matt Rambow / Colorado Norton Works

swooshdave · May 18, 2009

CNW said:
Hi,

The second reason for the post is in regards to the question about the -72 installation of our breather. We have designed and are making an adaptor plate that first mounts to the cases and the valve fits onto it.

Matt Rambow / Colorado Norton Works

Ah, thank you. That explain the slight reduction compared to other engines. The description on your site was a little sparse with that detail.

As for the rest of your response, there is no need to defend your costs. The market will determine if the pricing is correct. That is, before the government bailout of the Norton spare parts industry... :wink:

daveh · May 18, 2009

Question: what is the advantage of fitting the breather to the crankcase, as CNW has done so elegantly, versus allowing the engine to breathe through the timing case and fitting a XS Performance one-way valve, as Marinatlas has done with his 850?

chris plant · May 18, 2009

hi dave, as i see it not a lot

swooshdave · May 18, 2009

chris plant said:
hi dave, as i see it not a lot

I'd disagree. By breathing from the timing case the air has too pass through those tiny holes. Not very effective. If you bored some bigger holes it might work better with the valve.

The point is to control the pressure within the crankcase, not the timing case.

I'd be interested in hearing how later bikes breathed, especially the big singles (something like the Suzuki cruisers).

chris plant · May 18, 2009

hi swoosh,maybe you,re right but im not convinced,to me the timing chest is just an extension of the crankcase ,more volume equals less primary compression and to me thats what is needed

Ron L · May 18, 2009

If you read Jim Comstock's explanation in this thread http://www.accessnorton.com/crank-case-breather-t3680.html?hilit=crankcase breather&start=45 I think it will make sense.

Jim has done a lot of work on this design and it's testing. I very much admire his work and sound engineering on all his projects. I'm glad he is participating in this forum.

As to "copying" the design, I don't believe enough people are willing or capable of making or having someone make the parts to have any affect on Matt's sales. And whatever Matt charges for the device, you are free to purchase it or not. The market will determine what the value is.

Jeandr · May 18, 2009

CNW said:
Hi,

Couple of reasons for this post.

First I just feel like I have to say something about the copying of the valve we make. I certainly understand that nobody can protect themsleves from people copying product (except with copyright of course), especially if the parts have been proven to work. What does disturb me is that somebody is comparing prices the way they do. They are proud to let everyone know that they can take someones ideas, copy it, and do it so much cheaper. What these people fail to consider is that it takes a whole lot of money to develop these parts. The price difference is certainly not because there is a Logo machined into the valve body.

-Number one we have a whole lot of time, years actually, for Jim Comstock to fine tune and make sense of how this valve need to be made to work as well as it does.
-We have developed CNC programs for 3 different valve bodies and 1 adaptor plate. MKIII, standard and -72.
-We have to make vaccum fixtures for those above parts.
-We have to machine enough of those above parts to make sense of the setup charges and try to bury some of the initial costs to make sense out how much money we have invested in each part
-We had to design and make a fixture that works for all engine years that will allow us to make mill the mounting area on the cases.

If I told you what the above cost many would probably think we are a bit crazy for doing what we are doing. Heres the thing though. We like to develop and bring these kits and developments to the market so many can benefit from them....this is the American way to do business isnt it.. If after we put all this time and effort into all this and didnt make any money of the end products...well, we wouldnt be in business for long. There has been countless American companies that had to close their doors after some over seas companies copied their product and offered it for less. We are not a hobby business....we do this for a living and can hopefully do this for some time to come.

I know we are going to sell a lot of valves because they work very well and most individuals arent going to try to make their own. If some decided to make their own, that is fine to, as long as they dont go out there and brag how great they are for taking sombodies hard work and discounting it. Making us look like we are over charging because we have all of our startup costs that have to be paid for.

The second reason for the post is in regards to the question about the -72 installation of our breather. We have designed and are making an adaptor plate that first mounts to the cases and the valve fits onto it.

....why dont you ask Jean to make you a copy of one. It will be a whole lot cheaper than buying it from us !

Matt Rambow / Colorado Norton Works

Matt,

Don't get me wrong, I think your prices are very reasonneable considering the quality of the work you do and the time spent in developping these kits. I don't count the time I take to make these parts because it is a hobby to me and if I had to give myself even a minimum wage it would end up costing more than getting it from you. Compare this to cooking a meal at home and getting it at a fancy restaurant, the recepie is available, the home cooked meal can be satisfying but the meal made by a chef can have that touch given to it by the chef making it worth the extra cost. Some people can afford to eat at fancy restaurants all the time, I can't.

Jean

dave M · May 18, 2009

In response to Chris Plant's comments, I tend to agree with him. The CNW reed valve modification looks very nice but really requires the special facilities and machining skills available at CNW. For me that would require me shipping my cases half way round the world.

For most of us the repositioning of the breather, the addition of a PCV unit and crankcase modifications where necessary (these modifications generally also include additional breather holes through to the timing chest to equalise the pressure) are things that any competent enthusiast can do and probably just as effective, given average classic Norton use. They also seem to have stood the test of time which can be seen by a quick trawl through some previous threads. It has to be said that many of us on the forum have had thousands of miles of trouble-free riding with absolutely standard set ups. My own cafe racer based on an early camshaft driven breather valve model, was in quite a high state of tune and didn't leak any oil at all.

rbt11548 · May 19, 2009

daveh said:
Question: what is the advantage of fitting the breather to the crankcase, as CNW has done so elegantly, versus allowing the engine to breathe through the timing case and fitting a XS Performance one-way valve,

Hi Dave, is this the XS 650 Twin valve you are talking about? I am thinking of fitting one. I wouldn't have known about anything like this or any of the other improvement mods if I hadn't joined the forum, so for that alone it's been great....... wait a minute !!!!!! ... it's been bloody expensive :shock:

daveh · May 19, 2009

Thanks for the replies, guys.

Robert — yes, it was the XS 650 twin breather I was referring to. http://www.mikesxs.net/products-4.html?category_id=4.7
Ron — thanks for posting Jim Comstock's comments on his breather. I admire his work.

I guess the proof of the pudding is in the eating. If a timing case one-way valve keeps the oil on the inside, then it's a good and cheap solution. People on previous threads have reported satisfactory results from this system, but it appears that the CNW valve might be more efficient and might gain a few more gee gees, which is no harm. I have yet to fit a one-way valve to my 850, which is one of the reasons I asked.

Crankcase Breather

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