i have a problem my 400 overheating. Yes the rad is very clean . one thing i have notice is that cooling fan suck air through the rad rather than blowing it out the front. This i don't understand is this normal .

 

Yes that is normal............When you say your RAD is clean ...How do you know?
Did you look at the back fins where the fan housing is?
They get build-up there.............Caper............

 

I clean it myself and them also had the deal clean the rad

 

I have a 05 700 that gave me same issue for a while. I cleaned rad. and was 100% sure was clean. I thought the system was full of anti-freeze and still had problem. I finally tried what the manual says, " Burp the system to remove any air from system". Crank the atv up with rad cap off, let run till the thermostat opens and then gently squeeze the top hose slowly at the first bend, try this several times and hopefully will get the air out of system. This worked great for me and I was sure this was not my problem but found out it was. Good luck!

 

thanks i will try that

 

2 or 4 stroke?? any bubbles in the coolant when running??