...but not this time. My 900RR is bubbling over from, I guess, the coolant overflow container. Two or three times now, as soon as I park it, a ferocious boiling sound emanates from under the seat. Yesterday fluid escaped from the vent tube and got all over the back tire. The temp gauge does rise a little higher than normal in traffic, but at speed comes back down. It's analog, BTW, a little needle...you digital cowboys wouldn't have it.

Any ideas? Air in the system? Faulty water pump? Bad cap? I has no idear.

 

Check to see that the thermostat is working properly.

 

Either that or check your radiator cap (if they go it lets pressure back up through hose)

 

How much coolant in the reservoir when it cools down? I have heard of the same thing happening when air was in the system but that was only after the coolant had been changed. And that was on a Busa ... they gotta be 'burped' after a coolant change.

I'd check the coolant first ... make sure you have enough and test to see if it's the proper mix. Since it's not running overly hot I would not suspect the water pump or thermostat.

 

Hey, thanks guys. Got her back to cool...no boiling anymore. Another guy in the 900RR forum had the same thing and all it took was an extra washer on the radiator cap. Man, am I a happy biker now. Thanks, mate.