I have a 404 tubular that I've been having trouble getting air into. The last few times I've aired it up I've had to use a amsll allen wrench and stick it down the valve extender to jiggle the valve stem around and which would do the trick. Today I'm just not able to get the valve stem to open at all....any ideas?

Did you back the little locking peice on top of the valve all the way up (all the way open)? If not it could have rattled around and worked itself back so that it is preventing the valve from opening. I tighten mine in the up (open) position so it can't work itself back down from vibration. I've also seen an extender that used a little sealing o-ring that didn't go on right, part of the o-ring got tangled in the valve, this one acted like yours also.

I have a 404 tubular that I've been having trouble getting air into. The last few times I've aired it up I've had to use a amsll allen wrench and stick it down the valve extender to jiggle the valve stem around and which would do the trick. Today I'm just not able to get the valve stem to open at all....any ideas?

I have some valve extenders that actually have their own valve core, which grips and turns the tube's/tubular's valve core, as well, instead of just being hollow like most. They don't replace the original valve core, but work in tandem with it. They work great, as each time the original valve is opened and closed. You don't have to rely just upon air pressure or sticking something down the extender to open the valve, plus, you can close it up solidly for riding. They are slightly heavier, but more functional.

If the extender you have on their right now isn't too tight, you may be able to replace it with one of these without removing the tubular, if you are careful.

Excel, among others, has them in a couple of lengths.

http://www.excelsports.com/new.asp?page=8&description=Valve+Extender+50MM+With+Presta+Head+E ach&vendorCode=PS&major=1&minor=31

I have some valve extenders that actually have their own valve core, which grips and turns the tube's/tubular's valve core, as well, instead of just being hollow like most.

Wow, I never knew there was such a thing. I just ordered a couple. I could never get the pressure as high or even gauge the pressure with the regular extenders.

:cool:

Use some teflon tape on the threads of the valve stem before you thread the extender on, helps to keep it from leaking air.