Valve Core Replacement

[Guest]

Bike sat for 10 days while I replaced all the valve shims (thanks Ray!). I get back on and the front tire is flat. This is after no problems since I owned it. I spray it down with soap and the valve is leaking. Ok, that's fixable. But the auto store had only one option for valve cores and it's the left example in the photo. The black banded core came out of the Dunlop tire as you see it, with the spring extended. Is that normal or is that the reason it was leaking?

here's what I read about the red or black band....

[FONT=&quot]"A standard valve core usually has a black seal with a temperature range of between -65?F (-54?C) and 225?F (107?C). The high temperature core usually has a red seal and has a temperature range of -65?F (-54?C) and 250?F (121?C) and is designed more for use in truck applications." Better wording may have been "any higher temperature application."

The red core is now holding air fine so it's staying in there but I am curious what happened to that black banded core.[/FONT]

 

[storm 64]

Humm, maybe age? Maybe the black rubber one just dried out... What condition is the rest of the valve stem like? It may be dried out too...

What part of Arizona do you live in?

 

[Gorminrider]

Interesting! though I don't see much difference in the temperature specs to matter. From wikipedia, the one with the long spring and black band is the OLD type and that might be more pertinent...aged out.

 

[Guest]

Interesting! though I don't see much difference in the temperature specs to matter. From wikipedia, the one with the long spring and black band is the OLD type and that might be more pertinent...aged out.

it seems it's a long spring design rather than a core that exploded. The valve is definitely defective but the length of the spring isn't the defect. I'm not sure why they put a long spring in a motorcycle valve stem but the new short one is holding air fine. The tires aren't as fresh as I thought they were. close inspection shows some sidewall cracking. The tires are only a few years old but I think the heat in Vegas aged them rapidly rather than use. The valve stems are average condition. The bike came from Chicago via Las Vegas and has only been in Flagstaff, AZ for a few months since I bought it.

 

[Steve]

The tires are only a few years old ...

They might be older than you think. Have you checked the date codes?

.

 

[Guest]

good advice.
they were installed in 2012 but are from 2010 and 2011. barely 2k miles on them but the dry rot on the front tire is a deal breaker.
another reminder to ignore anything the P.O says about the bike he's selling. "Newer Tires" = "Tires that need to be immediately replaced."