Cooling problem

Hello members of Thumpertalk!I am wondering if anyone can help me with a cooling system problem.My 2006 WR450F starts leaking coolant out the weep hole after idling for about 10-15 sec. after completly warmed up.I changed the seal directly behind the rotor,it still leaks,I tried a rad. cap off a `05 Banshee incase of a bad cap,no change.If I start driving it the coolant stops leaking,the overflow is going down so the cap must be good.My dealer says it could be the thermostat, but it does`t have one.Also, from day 1 it was coming out the weep hole a little bit Yamaha said it was because the factory over filled it.It never leaked enough to lower the overflow.Can some one PLEASE give me some advice on this pain in my @#$


I had the same problem with the 450 -03 I just bought. The person that owned it had installed the oilseals the wrong way. And second he hadnt lubed them up with lithium based grease.. The result was that the impellershaft was worn down..

I did a quick fix with new oilseals and made sure to polish the impellershaft as good as it could get. Had some severe wearing marks on it.. Looked like a tooth who had been to long in a glass of coke..

Anyway, I made sure to stuff the room between the two oilseals as full as i could get it with that lithium based grease.. And ive been problemfree for the last 400km..

Its important to install the oilseals the right way, if not they wear faster and they wont be waterproof.. it you look at them. youll see that there is a pathern (not sure if thats the right word) on the surface facing the chaft that pathern "propells" the water back into the coolant system, making sure it dont get past..

Its also important to use a good coolant that lubes the oilseals, you dont HAVE to use that kind of coolant, but a good coolant woul make sure your oilseals last longer.. (I think its infact not allowed in roadracing due to the problem with extreemly slippery road if a bike should start to leak)

So.. replace the oilseals, and the impellershaft if you need to. Lube up with as much lube you can get in there, mount the seals the right way(refer to manual). If you are sure you done all this and it still leaks, I guess you have to ask somone else with a litle more experience..

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