i have a 85 yamaha tri z and when the engine warms up, the coolant will go into the resevoir like it is supposed to but when the engine cools down the coolant isn't being syphoned back into the radiator. why is it doing this? do i have a bad radiator cap and if so are there any other tests to perform on it to make sure that is the culprit before spending $30 for a new one. thanks for the help. [img]i/expressions/face-icon-small-happy.gif[/img]isgust

 

THANKS FOR THE HELP

 

That sounds right. you should be able to force water back through the cap with a hose. it will have soem resistance but it shouldn't take but a pound or two force to check it. if it doesn't do it the valve must be stuck. you may be able to clean it instead of replace it.

 

Take your radiator cap to someplace like Autozone, they will test it for free & then you'll know. They will probably have one that fits for $8.

 

thanks for the great idea. i will give auto zone a try to see if they can test it. later

 

Don't forget to check your resevior coolant hose fit. If the hose that takes coolant back fits loose at either end, it'll suck air instead of pulling coolant. With an old bike like an 85 tri Z, your hose may be getting hard an brittle - I'd check that first.