I've posted this a couple places relating to tubulars before but it's still relevant to your question, particularly about clogged valve cores, etc...parajba wrote: ↑Thu Oct 17, 2019 7:11 amTwo quick questions:
1) I need to top up the Orange sealant in my 5000TL 25mm on my CLX50s. Are there any videos online to explain what I need to do?
2) The valves seems a bit off. The little pin is not as snappy as before. I guess they have slight clogged as I have been using them for 10 months. They still work though, I can still inflate the tyres but it takes a bit more effort. What should I do?
I never use sealant as a "preventative" measure in my tubulars, as it can potentially stick your latex tubes together if they are allowed to go flat, but more than that it also means you would never be able to use that tire as a spare once changed out for a newer tire. But I do use sealant to fix punctures, rare as they seem these days, while on the road. And occasionally, the sealant may ultimately clog a presta valve in a way that prevents you from pumping up your tire. Even though you unscrew the top of the presta valve, it is impossible to pump air into the tire. So, out of curiosity what it was that was actually clogging, I did an autopsy on a presta valve that would not allow any air into the tire.
What happens is the sealant gets in the valve, and for whatever reason, perhaps you didn't quite screw the top back down all the way for example, as I think happened here, the sealant pools and forms a nice little o-ring so perfect that you might think it actually is an o-ring intended to be there....
As it is above, that "o-ring" on top will quickly act just as the valve on the inside of the presta valve acts to prevent air escaping... it immediately blocks the passage of air throught the valve into the tube.
Simple solution... dig that sealant based latex o-ring out of the valve and prest-o... your valve core is free again...