08 ktm exc250f-w over heating with athena big bore kit

I am having overheating issues with my bike. I have an athena big bore kit on it that was installed prior to purchasing the bike. Radiator cap is 1.6psi I am running engine ice in it. Seems to over heat about a hour into riding. I do have radiator guards on with no punctures or leaks to the radiator. I am thinking either jetting, needs a new and bigger water pump, needs a radiator fan, or the head gasket may need changed out because so restriction from the gasket. These are the outcomes i could think of any help would be greatly recieved.

You must have a BB KTM 250 XCF-W. Under what conditions does the bike overheat? Does it overheat when moving at a decent pace and when the engine is not being pushed very hard? Did the previous owner have any overheating issues with the bike? Possible solutions: Replace radiator cap with the proper stock 1.8 unit. Some rad guards do not allow for enough air flow. I highly recommend a fan and a coolant recovery system, especially for technical, strenuous, slow moving situations.

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