zzr250 overheating prob

[Cwidova]

hey all, a friend of mine has a zzr250 which overheats and also engages the thermo randomly....we have changed the fan switch, radiator cap & checked all the wiring but nothing helped....the bike always overflows water and runs hot as well as engages the fan whenever it feels like it!!!! for the time being we have bridged the switch so that the bike doesn overheat(according to the gauge) but we don't really want to leave it like this as it probably not good for it.......is there anything that iwe hae missed or anyone else had a similar sort of problem??

[cookeetree]

Flushed the radiator?

[Cwidova]

yeah the radiaor has been on and off a few times and we flushed it out one of the times......we ran fresh water through the engine while it was off as well......lots of crap in there but the problem still there

[P4nza]

CHANGE the radiator itself

[Cwidova]

the radiator is in pretty good nick.....no cracks, leaks & it flows well......when the fan working as it should there no problem at all....it is only when the fan fails to kick in at the right time the bike can't get cool enough!!!! when the fan "hard wired"(bypassing the switch) it stays under operating temp.....

[Six Addict]

would the fan not be connected to a thermostat??

ie if u put it thru the thermostat but its buggered then the fan will never know its hot enough, but when u hard wire the fan on its sweet??

just a thought from a reasonably not mechanically minded person

[Cwidova]

yeah we changed the sensor/switch in the right side of the radiator but haven changed the thermostat....prob give it a shot tonight

[mike-s]

new rad cap?