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Radiator fan on DRZ400E

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I've been thinking about doing the same thing, but I am worried about one little thing.

When riding and the fan is not powered, won't it induce quite high voltages? And if the fan is turned on while riding but the blades turn because of the wind, it will basicly act as a short circuit..

How do you control your fans? Temperature? or manual switch?

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Have a look around and see if you can get the big metal bladed fans...

Comair rotron used to make them...

They are loud, but thats not going to be a problem on a bike :banana:

150cfm air flow, and it should be more robust than a plastic fan...

Either way though, I agree that the fans need to be fitted so the air is drawn through the rads (so it pushes air towards your legs)

Mind you, a couple of fan guards wouldnt go amiss either....

Hey, get some metal bladed fans and fit them to the front of the rads....

Then they double up as rad guards :eek:

Chopping anything that trys to hit the rad🤣😉

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I thought they were 120mm fans....

Sorry :eek:

I might fit a fan to the right hand rad on my 400S...

I never have understood why manufacturers make bikes with 2 rads (DRZ, VTR, VFR's for example) and then only put a fan on 1 rad :S

I was told by a local bike shop parts guy that its the cost...

but a damn fan that costs the manufacturer less than £50, isnt going to affect their profits is it?

Are you going to fit a fan in the airbox?

Cheap forced induction? 😉👍:banana:

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I'd like to get some fans as well.

I know little about computer fans, but I'd stay away from "sleeve" style fans. Go for a two ball bearing or ball bearing fan....especially on an E.


seems like a good one; 80 CFM, 2 ball, 25.5mm (thick), $12.99


79 CFM, ball bearing, 25 mm, $6.99....seems pretty hard to beat 79 CFM for $7.


Heck, might by a couple right now. One on each side at 80CFM is plenty of air movement. There will be weeks, you won't even turn them on. Like someone previous said, it's that tight single track climb that always gets ya boiling.

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If you have stock E radiators with UNABIKER guards... there is no place for bigger fans. Maybe if you modify right unabiker guard. There is much more space.

But i think it's more efficient on the left and hotter radiator...

Now it's working good. Not possible boiling with running fans.. Now it depends on fans lifetime :banana:.

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I had mine ('02 E) boiling so much, it was coming out the overflow tube of the overflow tank a couple weekends back in crawling speed uphill singletrack here in AZ. Granted it was well over 100 degrees outside, and the overly tall stock gearing was making me abuse the clutch quite a bit. Maybe a little fan would help out...


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I know Mattydiah says no computer fans, but I'm going with them. And I plan to have the same success others on here have talked about. How many times do you take your E in deep enough water to submerge the fan. Once and a while right. If your going through deep water you probably aren't on terrean where you'd be using the fan anyway. Many electrical components can be soaked and as long as they aren't on or shut off quickly and dried before use, they generally work (see all the cell phone examples). Both examples I posted should fit under a Unibiker (I'll be attempting to make them fit). Besides, the fans I posted were all under $12. Is it worth not boiling over your E? I believe it is. I'll post my fan project when I finish.

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One problem, which may be serious, is when the connectors inside the fan get wet from dirty water they will create a short-circuit. Depending on how you have connected the whole thing you will either blow a fuse, fry your wires; or drain the battery. Simple fix is to add som silicone or around the connectors, making them more or less waterproof.

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Computer fans are tough things really...

They will even work in oil (just a lot slower)...

I have played around with them, and submerged them running and they work just fine...

The only time you will get a problem is if you turn them on underwater...

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All of the PC style fans I've ever seen and played with do not have contacts. They are a transistor controlled brush-less design - perfect for bike used.

If the motor jams the current does not increase, also I'm don't think the fan can generate any voltage when free running as the motor can't turn into a dynamo.

I run mine from a switch which I flick on if I'm forced to travel slowly.

Here it is on my 2000 E. The rad pipe style on this model makes it easy to install on the LHS rad. The RHS has pipes in the way.


It's a pretty punchy little fan too - you can really feel the heat being drawn out and existing the shroud when using it.


I've had it on there over a year now with no issues. I've probably never submerged it but I show it no real care when jet washing, in fact most of the time I forget it's even there.:banana:

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