Running Track Bike without Fan

[Mito]

Hey Folks, I'm in the process of re assembling my XB12 track bike that I got as a bit of a wreck a couple of years ago. I have removed all of the bits not needed for a race bike like charging system, starter (will use pit rollers), lights and extraneous road gear. I need to make a decision about keeping the cooling fan or not. The ignition will come from a total loss battery so wanting to keep the electrical load low. I won't be using the sub frame under shield so air flow through the frame will be good. Has anyone had experience of going fan less?. Cheers, Stu

 

[Cooter]

Weight matters, but much, much, less in a torqu-ey bike. The fan weighs less than if you skipped breakfast, but since you've already gutted the crap out of it...

Contrary opinion, but fact: The fan is only effective under 25mph or less.

So when you get off track, go straight to your pits. Put on a large RSS (right side scoop), datalog your temps and choose your oil weight accordingly.

 

[outthere]

Removed my fan long ago. No issues so far.

 

[Mito]

Cheers Cooter, pretty much what I was thinking. Weight was not really the focus.......my weight is though. I trimmed 12kg out by not using the charging system, starter and battery. Where I hope to get gains is less rotating mass so easier to spin up. It's a fun bike so enjoying the tinkering.

 

[Kurlon]

While you're chasing rotating mass, Evolution Industries makes aluminum replacements for the front primary sprocket and front belt pulley (if you're not already chain drive). If you're still belt, you can get a lighter rear pulley out of France.

 

[34nineteen]

I'm building a XB12 track bike also. I considered ditching the fan, but (almost) learned my lesson the hard way with my R3 trackbike with the fan removed. Everything was great while we were running, but we got red/black flagged off track and my poor bike almost cooked itself while we were lined up waiting for the flag to clear. I had a choice... turn off the motor, but then deal with heat soak.... or let it run and hope the flag cleared before the head gasket gave out.

So, that said... I put the fan back in after that. And I'm running the fan on my XB track bike also.

Magnesium Mike wound up knocking a few of the magnets off his charging rotor on his street bike and the fan wound up draining his battery faster than the charging system could keep it going. He realized this after the voltage got too low and the ECM shut off the bike. So, this would tell me that you will need to ditch the fan to run total loss..

This was with a full capacity lithium battery also. So, with your total loss setup, its probably really good idea to put a voltmeter on the bike to monitor how much juice you have.
It would suck to be "that guy" who "ran out of gas (or electricity)" on during the session, especially if they wound up having to red flag the session until they got you off the track... Plus it would also suck to have to wait out several sessions (or the event) waiting for the battery to recharge.

Instead of that, I decided to run XB9 gearing on mine to help drive out of the corners. We'll see how it works out for realsies if I ever get the damn thing finished.


I'm not trying to be negative about this and would love to hear what your actual real world experience is with this. Keep us posted!