I have a 05 Z400. When I first got it the fan would come on, I dont want to say regularly but atleast a couple times everytime I rode. I got a full yoshi exhaust and had to take my thermostat off the front of the motor in order to get my stock headpipe off and the new one on. Now my fan never comes on. I asked the dealer and they just said "it takes alot for those things to heat up, there is nothign wrong with it" I just cant believe that since it used to come on and now it doesnt. Is it easy to mess up the thermostat? I put it back on the same way and it looks fine. Now my coolant level is slowing starting to go down everytime I ride...what does this mean? Thanks for the replies

 

Sounds like you either have a leak or it's getting really hot.Have you checked for leaks?I figure you have,just thought I'd ask.