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Old 12-08-2012, 09:32 AM   #4
Hondo OP
What if its a Samsquamch?
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Joined: Aug 2006
Location: Denver, Colorado
Oddometer: 9,807
KLX450R Cooling Fans

While the stock KLX450R has dual radiators, I wanted to avoid coolant boilover when pushing the bike hard at low speeds & high altitude. As altitude climbs, the boiling point of the engine coolant will decrease, increasing the bikes likelihood of boilover.

To reduce this problem you have 3 options-

1- Increase the pressure capability of the radiator cap (higher pressure, higher boiling point)
2- Upgrade the coolant to Eco-freindly coolant (higher boiling point)
3- make an active cooling fan system

I chose to do 2 & 3. I will reserve #1 if I have any problems.

I searched online and found a guy on eBay that takes computer fans of all sizes and waterproofs them. As an off road bike I felt that these fans were a good investment over a cheaper, stock computer fan.

Here's a video of the eBayer watering down a fan-

I bought 2 each of his 12vdc, 92 mm fans-

My plan is to have the 12vdc fans run off of the battery, through a switched 12vdc relay, controlled by a switch on the Highway Dirt bikes top clamp. I will install a red LED in the top clamp above the switch that will light whenever the system is on. The coolant temperature will be monitored using the sensor that was included with the Trail tech Striker.

Here is one of the fans- I decided to go with the plastic fan guards to eliminate corrosion-

The ADDA fan - these are good fans. They are 70 cfm fans, so they will provide approx 140 cfm of cooling-

Ready for installation-

Here is the water temp sensor & the radiator crossover tube that it is installed in-


I wired the relay into the electrical system so that I would be able to run the fans whether the engine was running or not. The fans pull a measly .62 amps (7.5 watts) together, so power consumption will not be an issue.

The right fan had to mounted low on the radiator due to obstructions. I tied this coolant tube to the frame to ensure adequate clearance-

Then the fan fits in the space fine-

I attached the fan to the radiator using zip ties, rubber washers, and nylon washers. The rubber washers went between the fan & the radiator, and the nylon washers went between the radiator & the zip tie that was used to hold the fan in place.

Here's a close up of the left side before I trimmed of the ties-

The right fan-

The left fan - I was able to mount it higher on the radiator -

Here is the switch & LED on the Highway Dirt Bikes Top clamp- it is the RED push button switch-

No clearance issues with the Unabiker Radiator guards and it seems to help with cooling the bike at slow speeds.
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Hondo screwed with this post 08-10-2013 at 08:00 PM
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