Just started bike up the other day to run in rebuilt engine and notice a problem with water been squited from the to radiator vent pipe through to the HRC expansion bottle mounted near the side of the engine?

So what i did is i remounted the bottle higher up to the top fairing bracket with a longer pipe. Still no joy!

Every time i rev the bike it shoots water in to the bottle and then starts to overflow. Can any one tell me why it doing this and how i can stop it.

cheers , Kevin.

If it's pushing water into the bottle before the bike is close to overheating then you have a head gasket leak.

Even when the bike is stone cold and you give the throtle a blip it squirst water up to the bottle. If you take the cap of when running you can see the water running very fast from the thermostat to the top radiator. i was wondering if because it has had the radiator altered to accomadate the ram air , it was causing a restriction. But havnt said that the bike has been running with this top radiator with the last owner?

Knackered rad cap?

I had one that was filling up the expansion bottle as soon as the bike got anywhere near lukewarm

You can have em pressure tested or find a spare one.

Neosophist wrote:Knackered rad cap?

I had one that was filling up the expansion bottle as soon as the bike got anywhere near lukewarm

You can have em pressure tested or find a spare one.

Eye i think you might be right there, water must be passing through the seal and escaping up to the expansion tank. Wonder if the cap of anothe bike might work?

Off a honda probalby...

It'll have the opening pressure on the top.. should be 1.1mbar I believe.

Make sure it's the same pressure otherwise it wont open right.

Water needs to be under pressure to make the boiling point higher.. if your caps knackered as soon as the water expands with the heat it'll just fill the bottle.

I think I paid £18 for a new one but most Honda bikes use the same cap.