KDXRIDER.NET

Need some help. I have a 98 KDX220 that I let my son have. He rides it just as hard as I did but when he shuts it off we hear the radiator boiling. Haven't spent anytime tearing it down yet but what would be the common problem. The engine had a total rebuild top and bottom about five years ago but I didn't do anything with the water pump. I replace the top end every year with out fail. Blown head gasket? Nee to tear it down in the next couple of weeks. Any help would be appreciated.

You can hear the radiator boiling when it shuts down? Might be because the radiator fluid isn't flowing now, but is still in contact with the hot engine. Soon that pocket of fluid gets hotter and you can hear it bubble.

Is it boiling over while riding? Or you only hear the sounds when its shut off?

are you loosing colant?

Sorry, just got back in town. The bike is not loosing fluid. But it boils hard when we shut it off. Don't know if it boiling when we are riding it.

I have another KDX so I'll switch the caps and see if it follows the cap.