Do track bikes need a radiator fan?

[Lucius]

As the title says, do track bikes need a radiator fan? Just wondering if i can ditch it...

[Thirsty]

Im not sure, but maybe if you were entering Superstock you probably have to?

[Lucius]

Good point, didn't think about that. I'll have to check the reg's.

[Lucius]

Nothing in the reg's about it.

[Falcore]

How long would one spend idling? Fan isn't needed above 60kph roughly.

An would take a couple of minutes at stand still to get to hot

[Lucius]

Yeah, that's what i was thinking. And if it gets hot from being held in the dummy grid you can allways just turn it off.

[Arwon]

At collie my bike runs at 90deg on a 31 deg day, so as it heats up so will your bike, every time I stopped it was on the fan. Is the weight loss that important for your level of competitiveness ?

Personally I will keep the fan

[XXX3]

You definitely need a fan.

People have removed one of two fans on their bikes and boiled the radiator *cough* Chitto *cough*. Also switching off the bike does not cool it down quickly - the coolant stops circulating and they actually get hotter in the short term. On really hot days over summer, by the time you've completed the cooldown lap and made your way to the pits the bike will be running hot. Remember also we have to run water to race which will boil at a lower temperature than coolant... not much margin for error.

Additionally for superstock, in the rulebook there's a statement that basically precedes everything else saying "your bike must be as standard EXCEPT the following..." so if it's not mentioned, you'll are required to have it.

[Lucius]

Cheers, guys. Think the benifit of having a fan out weighs the weight saving...

[Orangeninja]

You would loose more weight chucking a shit before a race then ditching your fan. For how much it weighs I think it's worth keeping

[Old frt]

You not only get held on the dummy grid at the start of a race, red flag situation may see you sitting there waiting for a restart and as previously stated, the engine temp increases once it's switched off.

[ripper1199]

You can consider removing the thermostat though. Gives more coolant flow. Monitor however that she is not running too cool. Removing the fan also means higher air flow through the radiator. I would certainly try it and had it on my race bike (running it usually in 30 degree weather -hot day in temperate climate, normal around here)
As to weight reduction and having a dump: I heard that a lot when I started asking a lot of questions of how to reduce the weight 33 to 50 % of every single piece that makes a motorcycle. Economists say "A billion here, a billion there and soon we talkin real money".
A streetlegal bike like a CBR 125 at 127kg can shed 50 (fifty) kg on the way to become a race bike. What might a heavier bike be able to shed. It all ads up.
To the issue with she heats up after stopping the engine. Cooling systems nowadays don´t work as thermosiphon cooling. Sometimes the fan comes on when she is stopped, but there is no actual cooling in progress...
Some people have an electric driven waterpump. The one used in Wabco park heaters is pretty awesome for that application. You can adjust the waterflow, the waterflow is usually higher than with the motor driven one, the engine can actually be cooled when she is stopped after the race (with a fan installed that is), More horse on the crankshaft if driveline is removed, and if the bike has no alternator and is running on battery only, there is even more horse on the crankshaft...

[Heretic]

You can consider removing the thermostat though. Gives more coolant flow. Monitor however that she is not running too cool. Removing the fan also means higher air flow through the radiator. I would certainly try it and had it on my race bike (running it usually in 30 degree weather -hot day in temperate climate, normal around here)
As to weight reduction and having a dump: I heard that a lot when I started asking a lot of questions of how to reduce the weight 33 to 50 % of every single piece that makes a motorcycle. Economists say "A billion here, a billion there and soon we talkin real money".
A streetlegal bike like a CBR 125 at 127kg can shed 50 (fifty) kg on the way to become a race bike. What might a heavier bike be able to shed. It all ads up.
To the issue with she heats up after stopping the engine. Cooling systems nowadays don´t work as thermosiphon cooling. Sometimes the fan comes on when she is stopped, but there is no actual cooling in progress...
Some people have an electric driven waterpump. The one used in Wabco park heaters is pretty awesome for that application. You can adjust the waterflow, the waterflow is usually higher than with the motor driven one, the engine can actually be cooled when she is stopped after the race (with a fan installed that is), More horse on the crankshaft if driveline is removed, and if the bike has no alternator and is running on battery only, there is even more horse on the crankshaft...

nice, what was your race bike?

[ripper1199]

CBR 138RR. You can see the electric waterpump in front of the motor. The Plug just left of it is covering the hole for the original waterpump. Driveline was removed so it needed filling.
030210202507_sonstige_andere_seite.jpg

[SomeBloke]

I build open wheeled race cars as part of a worldwide university competition (motorsport.uwa.edu.au) some teams decide to run without a fan and quickly learn that a fan is necessary, fans move air over the radiator elements, if you are stopped for what ever reason your temp will continue to rise, sometimes even moderate speeds dont allow enough air to pass over the elements, we use an RC plane motor (brushless) and blades from an online shop (being a uni team students run research projects on various blades) we have an insanely light package and a really energy efficient one at that.

I would leave the thermostat in unless you have an electric waterpump (with which you can control water flow at different speeds).

If you cook an engine because of leaving a fan off you will be kicking yourself, murphy hangs around waiting for these things..

[headbolts]

FYI when you remove the thermostat it does take longer for the bike/car/whatever to warm up and reach operating temp, but once there alot of bikes/cars ect run hotter actually with no thermostat as the coolant flows faster as isnt restricted by the thermostat anymore and passes through the radiator quicker so it doesnt cool down as much.

[SBK Toy Store]

My racebikes have always been fan-less. I haven't hurt one yet (well, at least not from removing the fan...).

[TheBrad]

FYI when you remove the thermostat it does take longer for the bike/car/whatever to warm up and reach operating temp, but once there alot of bikes/cars ect run hotter actually with no thermostat as the coolant flows faster as isnt restricted by the thermostat anymore and passes through the radiator quicker so it doesnt cool down as much.

Spot on.

Also as the bike is cooler it richens your ratio to compensate for the colder temp meaning more fuel needs to be carried.

[darkfibre]

My racebikes have always been fan-less. I haven't hurt one yet (well, at least not from removing the fan...).

How does your climate compare to Perth?

[SBK Toy Store]

Hot and steamy (think India).