I know this is an old thread but I just started having this problem with my 700-4. I've had the bike for over a year and put it through alot. Did some trail riding two weeks ago had no problems. Then today some light riding around the camp and it overheated. Coolant bubbling out, I loosened the cap and it seemed to have a bubble. I filled back up, temp dropped to three bars and I went on. Shortly after I hooked a trailer to it with a 5x5 box stand on it, and pulled it out of the woods, there was some pretty good strain on it and never heated up, but then on flat ground under light loud it overheated again.
I stopped coolent was boiling let the fan run for a min, then turned key off then cranked back up and temp dropped.
The radiator was a little dirty but not any different then the on previous operation.
I did a full cleaning of the radiator this evening.
Any ideas if this still happens.