Overheating sidewinder 2017. Head gasket?

[Yamarace998]

Hello. I got a little problem, my sidewinder is overheathing on high rpm/full throttle and push colant in the overflow tank. Goes up to 110+ degrees celsius on wot and goes down to 70-80c after i let go on throttle. No high temp on cruising speed on trails. No oil in water, no water in oil, changed the colant and filled new one with a vacum filler to get all the air out. Checked the colant pump, its ok. No white smoke. Have some one had this issue before? Im thinking head gasket but dont wanna take the head off before I know better. Thomas, Norway.

 

[Confused]

You 100% sure it's bled of air? While your situation doesn't sound like a typical air in coolant issue, It's good to make sure before going too deep. The bleeder by the turbo is where most of my air came out. Mine runs perfect temp wise now. Before it would overheat even in the best of snow conditions.

 

[Yamarace998]

Yes, have bled it several times. Found tiny black flakes in the colant tonight so think it is from the glue from the headgasket. So I think I have some work..

 

[Confused]

Can you put a pressure tester where the radiator cap goes and see if you have combustion pressure in the cooling system?

 

[Turboflash]

Based on observation of that black head gasket coating now in cooling system, IMO head gasket is toast.

 

[mr. bwok]

Buy a combustion leak tester. Amazon sells them, there are also test strips at auto parts stores that do this. It will help diagnose head gasket leak. Shows if exhaust gas is present in coolant. May help with diagnosing before diving in deep.