WR450 Overheating

I just got back from a long ride in the dunes (80 plus miles). By the end of the ride the bike was puking oil out the airbox. I guess I must have overfilled but it couldn't have been by much, an oz or two at most. But it was spitting oil pretty good. I did drop the bike once in the dunes and it was upside down for about 5 min. Would that cause oil to run back into the airbox?

A few days later I am cleaning the bike and doing routine maintenance. I start the bike up and let it idle for about 5 min. Normally she takes a while to warm up but this time it seemed like she was running very hot right away and it sounded like there was a clacking noise on the right side of the engine. I recently replaced the radiators with some aftermarket ones. Did that before the last ride. Is it a coincidence that the oil puking out the airbox and the bike running hot happened on the same ride? The bike starts up and idles ok, other than the slight clacking noise. How can I tell that the radiator is functioning properly and circulating fluid? I noticed that there was a few drops of fluid from the left radiator. I popped the cap while it was still running (carefully) and the fluid was at the top and eventually started to run out the top. The reservoir has some fluid, just a little below the line.

What should I do to troubleshoot the radiator (or water pump) and make sure it is working properly? What about the oil issue? Should I be concerned about that?



Glamis, maybe Buttercup ??? Riding 80 + miles continuously in the dunes ? You had to have swapped to a bigger tank or had extra fuel in the neighborhood !!!

Anyways speed is a huge factor in sand. The slower you go the harder the engine works to propel the bike forward, harder working engine generates more heat.

Check your leaking radiator, an unsealed system will allow the bike to overheat. Check the radiator cap, make sure it releases at the correct pressure. Pressure test your cooling system once you fix the radiator leak to determine whether you have a leak elsewhere.

What year 450 are you running ?

We were riding between Patton and Test Hill and looping all around. I did refuel once to be safe. I have an IMS 3.1 gal tank. Works good except the tank lobes are so low the petcock is below the carb inlet tube which points up toward where the stock tank was. Do you know if you can turn down the fuel inlet tube? I tried but it was super tight and I didn't want to break it. So I have a long tube that loops up. Sucks cuz there's about a quart of gas I cant use and reserve is useless.

Anyway, not my real problem. I bought the Chinese radiators you see on e-Bay. My old ones were twisted. So i thought I was stoked on them. They seem larger, more cooling capacity and nice welds and fit perfect. I hope i didn't buy crap! Everything worked well for 90% of the ride. Didn't notice the leak until the end of the ride. I tightened all the hose clamps again so now I dont see anything drip. Can't see where the leak is coming from but I still see steam and can smell it. I know it's rad fluid. How do i pressure test the system? Do i buy some pressure tester from Pep Boys or something? If i find one what should the pressure reading be? Do i need to drain the fluid to test?

I need to get this fixed cuz i ride again on Sat. Any help is appreciated.



Can't see where the leak is coming from but I still see steam and can smell it. I know it's rad fluid. How do i pressure test the system? Do i buy some pressure tester from Pep Boys or something? If i find one what should the pressure reading be? Do i need to drain the fluid to test?

Yes, check with an auto parts store for a tester. Yamaha makes one, too. You should test with the fluid in it to help find the leak. The cap is supposed to open at 15.6 psi. I would give the radiators no more than 20 psi to test. The pressure raises the boiling point of the antifreeze, but not by alot.

Thanks everyone for the input. So the diagnosis was just a loose clamp fitting on the top hose. I guess we had a brief cold snap a few weeks ago and it might have shrunk things up a bit (Shrinkage!!!!):smirk:. So I think it leaked some rad fluid down into the fins. Once I noticed the steam the first time I tightened all the clamps again but still saw steam. I rented the pressure tester from Autozone (which they rent for free, just leave deposit) but it is only good for testing the cap. It had an adapter for a smaller motorcycle rad cap but no adapter to connect to the radiator. Cap checked out perfect. So i run it again and still more steam. Looking at it closely it looked like it was coming from the bottom where the ribs meet the tank. I suspected crappy interior weld so i took it to a radiator shop to have it pressure tested in a tank for $10. No bubbles, no leaks. So dumbfounded and frustrated i remounted it again and ran it again. Still steaming..... I had a trip planned for the next day on Sat so I just said screw it. I'm gonna ride her anyway. It must be some kind of funky residue left from the manufacturer.

So i ride all day on Sat in Glamis. No steam, no problems, no crashes, just another good day in the dunes.

So although i don't have any proof i think it must have been a just barely loose clamp on the top hose. Dripped a little fluid into the radiator fins and it just took a good solid ride to burn it off. I would have thought all the running in the garage to troubleshoot the thing would have burned that coolant off. I mean i let it run for like 10 minutes at a time at least 3-4 times..... But oh well, I'll take it. Chalk it up to Gremlins and shrinkage I guess.

BTW, Glamis was pretty tore up this weekend. Tracks everywhere... I guess between the New Yrs crowd last week and the rains, the sand was packed and rutted. My buddy on the quad practically rattled his fillings out. That's why 2 wheels is always better than 4!!!

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