I'm suspecting that my RST cylinder head has a crack somewhere because I keep hearing bubbles of water after I switch off the engine until it cools down, even though I've got the swirl pot.... which means compression is leaking from somewhere.

I found a 1.9 CVH (USA) modified cylinder head for a bargain. Is this the same as the 1.6 CVH head? If not what differences does it have? Thanks

 

is it loosing water then or getting hot loads of cvh's make that noise(bubbling in the hoses) just around the thermostat etc when a tad hot