I can chime in as I just installed the sump plug breather.
I am not going to offer any "professional" advice as to any breather or why or etc. I don't think I will have the ability to give professional opinion in my lifetime with these bikes. There's alot of stuff going on in there and I just don't feel confident in giving advice about everything. I can however share my experience.
I had an issue with crankcase breathing. I still *may have an issue. But I am working it out and dedicating TONS of time and energy into learning the bike and how the breathing system works from the top down.
I was having issues with the oil coming from the crank to the primary. I discovered the primary seal was blown out due to increased pressure in crank case.
Jim sent me a breather and I installed it. I noticed the oil still coming from the crank to the primary though.
I noticed a new leak though as well, this was coming from the oil lid in the oil tank.
Now I could have thought that the breather wasn't working or something like that but instead of jumping to conclusions I have been deducting conclusion from the symptoms.
I came to a realization the other day that the leak created from the oil cap must be increased pressure in the oil tank. This only happened AFTER I placed the breather in. The original timed breather did not create pressure in the tank sufficient to get by the oil lid seal. Now after this I ask myself why is there pressure i nthe oil tank? Well there was blockage in the tank breather.
So all said and done right now I only have one test ride but it was for 70 miles and things ran really well, I haven't checked yet but I suspect the primary did not get oil from the crank. I suspect this as my left leg is dry
Amount of pressure:
I dont know HOW much crank vacuum pressure the sump breather makes but it was alot more than the timed breather. I know it is a big difference as I noticed the oil coming from the cap when the oil tank breather was kinked.
Ease of installation:
You literally screw it on. It's got a fitting on the side for the breather tube that you tailor how it fits but that's it.
Quality of materials:
This thing is solid. It is machined beautifully and as well as solid it is discrete. It site where the sump plug goes so it is unnoticed. This also eliminates the tube going to the side of my timed breather.
175 bucks, now that's a healthy chunk more than the other breathers out there. But I think in my case going from the timed breather I did not have to do anything with the case so it was simple easy and I didn't have to rock the boat to install it. I can also take it off easy as well