crankcase reed breather

comnoz · Mar 18, 2012

Here is why I use a reed breather directly to the crankcase.

Here is a picture of a fitting I stuck on my bike, The hose runs to a water manometer.

Here is a video of a full throttle pull. You can see the crankcase maintains vacuum right up to just before the rev limiter kicks in at 7500 rpm. Click on the picture, turn up the volume and go to full screen, It was hard to get the manometer to show up very well but it is there. The the vacuum in inches is the difference between the height of the two columns.

See the next post for a new video link. Jim

comnoz · Mar 18, 2012

So Hannah [one of my teenagers] said if I am going to post a movie it needs to be better. So here is take two of the crankcase vacuum test. Click on it to view.

JimC · Mar 18, 2012

Hannah +1. No, make that: Hannah +100!

CanukNortonNut · Mar 18, 2012

Very cool Jim
I'm curious what E/I are you running?
CNN

CanukNortonNut · Mar 18, 2012

Also did you plug the timing side holes?
CNN

Hobot · Mar 18, 2012

How cool to see and hear the case venting and pressurizing. I"ve one of these on hand, its pretty sensitive, wonder if it'd work for this in my cases? It would be even more educational tedium to try the various PCV's out there, in various locations.

comnoz · Mar 18, 2012

CanukNortonNut said:
Very cool Jim
I'm curious what E/I are you running?
CNN

The ignition system is part of the fuel injection system. Jim

comnoz · Mar 18, 2012

hobot said:
How cool to see and hear the case venting and pressurizing. I"ve one of these on hand, its pretty sensitive, wonder if it'd work for this in my cases? It would be even more educational tedium to try the various PCV's out there, in various locations.

I have tried a lot of different check valves, but not with a regular manometer like I tried this time. I could never get a dependable reading with a dial vacuum gauge.

When I was doing the original work I had an electronic absolute pressure sensor in the tach drive hole. It put out 0 to 5 volts according to the absolute pressure. It was very fast reacting. With a scope connected I could watch the pressure rise and fall every time the pistons would rise and fall. At 2.5 volts out the absolute pressure was 1 bar so you could see what the average pressure was and you could see each time the reed valve would fail to open.

The reeds I am using can not keep up with the pistons at rpms over 7500 rpm and that is why the pressure starts rising. Jim

comnoz · Mar 18, 2012

CanukNortonNut said:
Also did you plug the timing side holes?
CNN

Yes, all the holes into the timing chest are plugged and a new drain hole has been drilled. Jim

stockie2 · Mar 19, 2012

Thanks Jim, oh and Hannah! Good to see what really happens. I would be happy if my XS valve works similar to that, and 7500 RPM is way past my normal operating range. Jim I have just the XS valve fitted to the normal breather line in and 850 to the oi tank. I have not altered any of the case breather holes. Is this something I should look at in my application or not?

Cheers Richard.

comnoz · Mar 19, 2012

stockie2 said:
Thanks Jim, oh and Hannah! Good to see what really happens. I would be happy if my XS valve works similar to that, and 7500 RPM is way past my normal operating range. Jim I have just the XS valve fitted to the normal breather line in and 850 to the oi tank. I have not altered any of the case breather holes. Is this something I should look at in my application or not?

Cheers Richard.

With the breather valve on the timing chest you can't block the holes into the crankcase or it won't work.

I have not tested the XS valve so I can't really make any good recommendations. Jim

rvich · Mar 19, 2012

Jim,
Is Hannah going to be our next Norton engineer-enthusiast? And I gotta tell you, I was relieved in that first photo to see some rust between the fins! Except if that is the Techline paint, was it the painter or the paint that failed? :?

Dances with Shrapnel · Mar 19, 2012

comnoz said:
The reeds I am using can not keep up with the pistons at rpms over 7500 rpm and that is why the pressure starts rising. Jim

Good stuff there Jim and a big thanks to Hannah. Looks like some solid product development and proof of concept; that's what I like to see.

So for those who race at and above 7,500 rpm is there hope for a suitable reed valve that will continue to scavenge?

comnoz · Mar 19, 2012

rvich said:
Jim,
Is Hannah going to be our next Norton engineer-enthusiast? And I gotta tell you, I was relieved in that first photo to see some rust between the fins! Except if that is the Techline paint, was it the painter or the paint that failed? :?

Hannah has been riding since a pw80 was big for her. I have to work at it to stay in the lead on the single track trails anymore. And yes, she is 17 and has placed her demands to have an e-start ready for her this summer although I don't see her getting dirty working on it..

Now my oldest daughter may be inclined to tear it apart just to see how it works. She rides a Hinkley Bonneyville.

That engine was built many years ago. It is just rattlecan paint on the barrels. The head was done with Techline coating but it didn't do well on the aluminum. It looked good for a couple years. The engine -inside and out is showing it's age. It is way overdue for a refresh. Jim

comnoz · Mar 19, 2012

Dances with Shrapnel said:
comnoz said:

The reeds I am using can not keep up with the pistons at rpms over 7500 rpm and that is why the pressure starts rising. Jim

Click to expand...

Good stuff there Jim and a big thanks to Hannah. Looks like some solid product development and proof of concept; that's what I like to see.

So for those who race at and above 7,500 rpm is there hope for a suitable reed valve that will continue to scavenge?

The standard reed will continue to maintain a vacuum to around 8000 if you are using the thin piston rings so they don't flutter. I have seen a little more depression at very high speed by installing two reeds stacked one on top of the other to make them stiffer which raises the resonant frequency. The trade off is more pressure down low.

The testing done on my old motor is about worst case. It has been thrashed on the dyno and the road for over 50,000 miles now. The leakdown is getting high and it is getting pretty noisy. It still only uses about a cup of oil in 2000 miles. I credit the crankcase vacuum for that.

rvich · Mar 19, 2012

How can you find time to work on your bike or your daughter's when you have to spend time working on OURS! Sorry about the poke regarding the paint, I couldn't resist. You have made it pretty clear in your posts that you are more about the mechanical aspect than the cosmetic, so don't start editing based upon my warped sense of humor.

I used the Techline paint on the barrels of my 850, which at present rate might be done before I get too old to ride it. The manufacturer actually recommended the non-professional line that does not require baking for holding up better to road conditions. Only time will tell. I guess I better put down the coffee cup and go out to the shop and put something together!

Russ

Dances with Shrapnel · Mar 19, 2012

rvich said:
You have made it pretty clear in your posts that you are more about the mechanical aspect than the cosmetic, ....

How can that be? He installed his forks upside down

comnoz · Mar 19, 2012

rvich said:
How can you find time to work on your bike or your daughter's when you have to spend time working on OURS! Sorry about the poke regarding the paint, I couldn't resist. You have made it pretty clear in your posts that you are more about the mechanical aspect than the cosmetic, so don't start editing based upon my warped sense of humor.

I used the Techline paint on the barrels of my 850, which at present rate might be done before I get too old to ride it. The manufacturer actually recommended the non-professional line that does not require baking for holding up better to road conditions. Only time will tell. I guess I better put down the coffee cup and go out to the shop and put something together!

Russ

Man, I was just getting ready to go out with my touch-up brush so I could take a new picture.

Actually if I was really into cosmetics I would have to take a touch-up kit to the whole bike. It looks like it has been USED.

rvich · Mar 19, 2012

You know the saying about food, "never trust a skinny cook".

pete.v · Mar 19, 2012

Is that like saying never trust a sober bartender?

rvich said:
You know the saying about food, "never trust a skinny cook".

crankcase reed breather

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