got a couple of questions

lower temp fan switch replacement, ive replaced the switch with the part no that comes up in the older posts, now the fan comes on way to much, you can have a good ride then pul up to trafic lights for around 5 secs before the fan is in, could some one check the fan switch on temp on there replacement so i can check ive got the correct one,

2nd im about to replace my rear sproket with a 41 tooth and have a 16 tooth front will a stock lenth chain fit if i spin the rear adjuster blocks round?