2 and a half hour highway drive ok?

The water gets sucked out of the overflow and back into the rad when the bike cools.

On cars rad shops can test the rad cap, I dont know if they can test the smaller ones off bikes tho.

Look at the cap closely if its warped or twisted or oval shaped replace it.

If your buying a new rad get a new cap too.

Honestly im just posting up everything thing I can think of because your rads not bent enough to cause over heating or need replacing IMO.

I just ordered a new cap I'm going to see if maybe auto zone can test the cap how much pressure should it hold?

Didn't see it mentioned, but your coolant mixture can affect temp also. If it is mostly anti-freeze, won't transfer as much heat as pure water.

It's in between -20 and -35 degrease farenheight I'd say about -25 that's the reading on the peak reader from autozone

I didn't check the boiling point it slipped my mind what temp should the reading be for boil over

did you ever fix this?

Put a new rad cap on and didn't have another issue until I took it full speed on the highway with the gf on the back but put a fuel programmer and haven't had the problem