APD326

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Sep 18, 2006
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I have a 2006 rmz450, I am having a coolant problem and can't figure it out. I can fire it up and it does just fine, However when I ride it (Hard) the coolant pours out of the over flow tube. I checked for coolant in my oil and the oil looks great (No Water), Also nothing is coming out of the exhaust and no sweet smell. I first thought it was the radiator cap, I replaced that, But still did not fix it. I replaced the radiators (which was not cheap) and that did not work either. Could someone please give me some ideas!!! The only thing else I can think of is the head gasket, I am so lost because the bike runs so good, but after about 2 to 5 minutes the coolant comes out. When I first noticed this I stopped riding ASAP. I did not ride long enough to hurt the engine I have never had this type of problem with this bike or for that matter any bike. Please help, Thanks for your time
 
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BSWIFT

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Is the water pump working?
 

Rich Rohrich

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If you are sure you are getting adequate flow through the cooling system it's fairly easy to check if the combustion gases are leaking into it and raising the pressure. Just attach a radiator pressure tester in place of the radiator cap and fire the engine up. You should see very little pressure rise with the engine running on the stand and a fan blowing on the radiator to get some airflow. If you see a fairly quick pressure rise it's a good sign that the head gasket is leaking.
 

APD326

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Sep 18, 2006
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We did a pressure check today and it looked OK !!! We are going to tear the motor down tommorow night. Any suggestions while its torn down would be cool. Other than looking at the gaskets, and the cylinder what else should we look for. Man this has cost me a bunch of cash, I went to 3 diffrent people and they all told me it was the radiator, now after buying new ones of coarse it wasnt the radiators and now they are saying it might be the cap. I replaced that and that was not the problem either. They are now telling me to send it to pro circuit. I really can't afford that so thats why im asking for advice.
 
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Rich Rohrich

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What specific procedure did you use to pressure test the radiator?
 

RMZRyder

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Dec 1, 2006
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I have an RMZ 450 2005 model and I wrecked pretty hard a while back and pushed my radiator into my fuel on/off switch. My radiator is in bad shape but still works, if you still have the radiators I will buy the from you to help lessen the finantial blow. I dont have any advice but I hope you figure the rest out soon. I live in ok also. :cool:
 

APD326

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Sep 18, 2006
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We had the bike on the stand, we used a blower and blew towards the radiators. My buddy took the cap off then fired it up. He took the tester and placed it into the radiator for a few seconds. A short time later he said the pressure was OK. I hope that is enough information for you. That is really all i can tell you about the procedure. Im pretty dumb when it comes to working on things. I better learn before i go broke on this 4-stroke though. Again thanks for your help
 

Rich Rohrich

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Any idea how much pressure built up, and how long he left the tester on?
 

APD326

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Sep 18, 2006
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Rich, I really dont know what the pressure was. He left the tester on for approximately 1 to 2 minutes and said it was good. Thanks
 
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Rich Rohrich

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What you have been describing sounds very much like a head gasket leak. You might want to try re-torquing the head bolts to see if it helps the seal.
 

BigRedAF

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Jan 9, 2005
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I hope this doesn't make me look dumb!

I have several years experience building engines but none on the RMZ450. Is there anyway that you could have put the head gasket on wrong side up?

If that's possible perhaps it would block a water passage on that engine and cause your overheat and boil over condition.

Just a guess, you experts go easy on me if I'm wrong...
 

BigRedAF

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Jan 9, 2005
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Your funny,

I noticed that after I sent it. Just bored to death in Atlanta tonight, my flight canceled do to snow and a diverted inbound flight.

This town bites!
 
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