Raidator steaming/overheating after extended idle?

I just purchased my new, pre-owned 2005 WR 450, YEA, and had it idling in the garage to charge the battery. I noticed the header was starting to get red hot...shortly thereafter steam started pouring out of a hose under the engine. I killed the motor and heard antifreeze bubbling and a little whistling noise. I have since looked in my manual and it says not to do an extended idle.

Did it just overheat or did I already break my new bike?!!!

Thanks and I look forward to participating in this forum in the future.


My bike did the same thing, nothing was hurt by it, i now use engine ice :applause: ,its by far the best coolent i have used.

Whew, thanks!


and had it idling in the garage to charge the battery.


At idle it hardly produces enough voltage to charge.

Get a battery tender. They are about $20 and come with a pig tail you can hook up so it can be charged with out removing the seat. You wont be sorry.

Don't leave that engine idling for any length of time. They will overheat really fast. You have a catch bottle under the left hand sidepanel, it sounds like the hose is disconnected or te bottle is missing. Good coolant is a necessity, engine ice or 60/40 anti freeze with watter wetter is good. The header glowing is normal. By the way, are all the free mods done on the bike? if not then you need to get them done and tell us all what you think after.

Man, a lot of good info. in a short period of time- thanks guys! Anyone figure out how to keep a wife happy 100% of the time (don't answer that question)?

I'll score a trickle charger and the right coolant. BTW my antifreeze tank was filling when the stream happened.

The only mod done on this bike is that the pipe has been opened up at the end. I've read things about cutting the grey wire, rejetting and getting rid of the throttle stop but I plan on getting used to the bike first before doing these mods. This sucker is a little more bike than the ol' XR125 I used to race as a kid-


Make sure you get a tender that automatically checks the charge and shuts off. You can wreck your battery with the types that don't shut off. I got a Black & decker charger maintainer from WalMart for $19. I think other guys have had good luck with the Battery Tender JR.


Depending on how and were you ride you may want to consider protecting your radiators. Look into radiator guard/braces. There are number of them out there and for around a hundred bucks you can protect them pretty well. I have Unibikers and they were a little difficult to install but have done an excellent job.

Most Yamahas are cold at start up but tend run hot soon after if your not moving. As said before Engine Ice and Water Wetter can help.

WR450F doenst have fans on the radiators and MUST be moving. Short idling periods or OK, but extended will fill up the coolant bottle and overflow eventually. Dont use the system, to charge the battery, will never catch up. Its designed to maintain a full charge under normal useage. Get a battery tender and hit it every now and then when its setting.

Coolant will eventually be forced out of the overflow resevoir and out the bottom of the bike. Engine ice is good but it will still overheat at an idle or on low speed high RPM rides, (i.e., pack and carry), NCMountainman has boasted the virtues of an Evans coolant on here, he says it's better than Engine Ice. I have not been able to find any, but my bike will still overheat in the right conditions and I am using Engine Ice ran through a set of Fluidyne Super Flo radiators....... :applause:

Wow, never had an overheat problem in Washington or Vegas (where I am now) with stock coolant, radiators, etc., but richer on the carb after doing the free mods and JD jetting. Shred, your bike is probably lean since it sounds pretty stock.

You cant idle these bikes without an electric fan on the radiator! :bonk::cry::cry:

Look at any trials bike or street bike and you will see a fan on them! KTM sells a hard parts fan that can be added to radiator guards for those low speed technical rides on Hot days. :applause:

Wow, never had an overheat problem in Washington or Vegas (where I am now) with stock coolant, radiators, etc.,

Goldbar :applause:

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now