Radiator Cap Failure symptoms and solution.

[BigMark]

My first component failure in 35k (I suspect the Radiator cap has failed)

The Bike runs nice n cool and the level in the expansion tank is low. When I stop or go through town I watch as the expansion tank fills and overflows.  (Even without the fan on) Given time the water retreats back into the mirky depths of the engine and shows low again.

 At first I thought I had overfilled it and just left it to find it's happy level (Triumph quirky)  but it keeps doing it without actually overheating. so I am guessing it keeps on sucking the air in and the bubble is getting bigger and bigger and pushing more water out as we go until one day there is not much in there at all  :?

So I need a new cap and I need to bleed the air.

I can remove the tank but that's where my skill stops.

Who sells new caps or better repacements in the UK?
How do I get ALL the air out for a fresh start?
Could I have come to the wrong diagnosis?

Edit: These Fat Fingers Suck!

[Mustang]

this may help
http://www.tigertriple.com/forum/viewto ... iator+caps (http://tigertriple.com/forum/index.php/topic,5994&highlight=radiator+caps)

especially about the 7th post by stretch ...........

and using other than a triumph cap is asking for trouble as some of the Stant caps don't seal as good as the triumph one
YMMV

[diggerT]

I have just had exactly the same symptoms and it was fixed (not by me!) by a new radiator cap. A triumph dealer told me they replace the caps every time the cooler is renewed.

Digger

[Sasquatch]

For some reason, the radiator caps out on the market today only last a couple of years.  The same goes for cars.  They are junk.  Probably only manufactured by a couple of companies world wise and reboxed for everyone else.  

A standard early Toyota cap works.  I replace mine every other year.