One Way Breather Valves, Revisited

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Jun 17, 2009
I have had the XS650 type valve in my breather line for two months now.
It is has done its advertised job of eliminating my various little oil leaks.
I has started "honking" lately so I took it off the line for an examination.
Blowing into it now takes considerably more effort than when it was new. Don't know why this would be,
and I suspect this is not a good thing.
So I purchased a motormike 80190 from Pepboys and installed it. Sure is lighter in weight and easier to install!
Anyone know how long these motormite's last, I have heard they need to be replace more often?
Why? the valve just wears out through lots of cycles?
The good news, to me anyway, is the motormite opens to allow air passed through much easier than the XS650 valve.
Hi High,
I don't know for sure, but I suspect that perhaps your XS valve needs more force to open now that you have used it is because of "stiction" due to being wet with oil, something similar to how oiled clutch plates stick together. I wouldn't worry about a little extra force needed to open it. When you jump on that kickstart lever and a cylinder fires there's going to be some serious pressure in the case as those pistons fall.
Regarding the motormite valve, I believe the flapper inside is just a rubber like material, which probably was not designed to stand up to motor oil or heat. I check mine once or twice a year, hasn't stopped working yet, and if it does for a few bucks I can get another.
I thought I'd check out the XS650 I installed on my bike about 350 miles ago.
I remember when I first started kicking the bike over I heard the "honk" but since the bike now starts first kick I can't hear it while running.
Right now my valve is at the top of the tank just before where the hose enters it.
The hose exiting the tank I terminate below my right pipe turned out at 45 degrees.
Today I filled a clear plastic bottle with water and while the bike was running stuck the end of the hose into it.
Pretty healthy flow of bubbles coming through so valve is at least working on the outward direction.
No oil leaks on engine so maybe helping me for that.

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