Went for a good dirt ride today.
The first without the cooling fan.

In my attempt to reduce weight, I removed the fan and mounted a indicator lamp, amber, on the dash that would light up if under normal conditions the fan would have come on.


Today was not a warm day, 12-15C.
Never the less, after 20 mins of really tight stuff the lamp came on for about 20secs.
Once a bit of air flow was established, it went off .
The thermostat goes off at a slightly cooler temp than the temp that turned it on so even though the the fan stayed on for 20secs, It is not likely that the temp rose too much.
On temp is 94-100C and off is 90-93C.

The red temp lamp did not come on and the amber lamp only came on the once.

Conclusion?
I think i will put the fan back on.
If it was required today, which was quite a cool day, then IMHO it is important.
Plus it's not as heavy as it looks.
If you could keep the speed up then maybe it isn't needed but I enjoy some really tight riding and therefore I need a fan.
And sometimes you can get stuck in difficult terrain and it can take awhile to get out.

Simply put, IMO it's not worth the risk.

 

I know that my fan comes on when I ride tight single track.

For me it's not worth taking the fan off either. If you aren't riding tight single I would say that the fan is not needed.

 

You guys are hilarious, I could take a dump and loose the same weight as the fan, come on just ride.

 

my fan comes on often enough to justify staying on the bike even though i'm all about losing weight.

 

i could lose a little weight from my fanny pack. still feels heavy even filled with lightweight motion pro goodies. peace of mind, though.

 

Just curious, can you guys actually hear the fan kick on/off? I've never heard my fan come, so I don't know if it has actually come on or not.

 

You can hear it when you are stopped. Just.
It doesn't come on very often and, for me at least, only when on tight, slow trails.

 

Tried the "take a dump" method.
Not sure it helps the bike much but I sure feel better for the experience.

You do have a point but for some reason I can't leave it be.
Always tinkering with something.
I don't think I have ridden the same bike twice.

 

I would not remove the fan for anything, it's come on often enough when riding slow/sloppy conditions. Yes you can hear it come on when riding slow, once you get a little speed up it shuts off quick. It comes on at 100 degrees celcius according to my Vapor

 

The thermostat temps I quoted were from the service manual.
The thermostat for the fan is located at the bottom of the RHS radiator so I can imagine the temp at the Vapor's sensor point being warmer.

I doubt the fan weighs as much as a lb so on balance it isn't worth removing.
Even so I'm tempted to leave it off to see if the red warning light ever comes on.