Cooling Fan Issue

[stnick]

If I let my bike sit overnight and crank it up the cooling fan comes on right at 1/2 on the temp gauge, just like it always has. The problem occurs after a long ride ( 200 miles) or so and the fan won't kick on until the hand is nearly 3/4 up the scale... I changed the sensor switch in the radiator.
What would be causing this to happen only after the bike has run for a while?
Nick

 

[kjcili]

did u change the switch b4 or after this problem started?

 

[stnick]

after... Also, bike never overheats while riding. I just noticed this problem while letting it idle with the skins off and "looking" things over. I don't do any commuting on the bike so no idling in traffic. I ride with a group and we play on the weekends. I bought it out of the crate and it has 22,000 miles.
Nick

 

[kjcili]

Have u ever changed t-stat & coolant?

 

[stnick]

I changed coolant about 10,000 miles ago when I put on the HMF exhaust. I started to replace the t'stat when I had the skins off but all 3 of my local dealers would have had to order the damn thing. They all said they seldom sale them, "they are pretty much bullet proof"!
Nick

 

[kjcili]

NOTHING man made is "bulletproof", except bulletproof glass. Any part for any car, truck, bike whatever can fail in an instant. but if it makes you feel any better, my gauge also runs high b4 the fan comes on after a good run.

 

[stnick]

Yes it does make me feel good to know it happens to someone else. Now I wonder why it acts that way? I've been in situations, like leaving a bike race at Barber Motorsports and heard the fan kick on but it's not a regular occurrence.
I think I'll put a manual switch in parallel with the sensor switch so I can turn the fan on when "I" think it's time.
Nick

 

[rubber2burn]

You might have an air bubble in your system

 

[dadofthree]

Are the radiators clean and clear of bugs, grass, etc. T-Stat, water pump ...

 

[stnick]

I burped it when I chaged fluid along with the new exhaust about 12,000 miles ago. I wouldn't think I could have air in the system that long.
My radiator fins are bent on the extreme edges from bugs and road debris but nothing major. The bike does not run hot... I just noticed the fan doesn't come on at the half way point on the gauge after it's been run for a while.
Nick

 

[dadofthree]

If the bikes not running hot I'd grip it and rip it.