Have four rides on my kx 450 fi. Installed the ktm thermostat shown here on, and started out with the bypass installed....like Allen said, motor did not built more than about 120 degrees on the first ride. Put a pressure gauge in the bypass line and when I plugged the bypass the gauge would hit between 30 to 35 psi. Although this pressure is only between the water pump and the thermostat, I worried this pressure MIGHT cause a internal leak that may dump coolant into the cases so I ended up installing a 1 inch long piece of 1/2 inch aluminum round stock with a 1/4 inch hole drilled through the center and that reduced the pressure spike to 20 psi max. This has kept. My bike at 150-160 degrees with it only cooling off on the ride off the hill only down to 140's. some are getting by just blocking the bypass off, but if you are not comfortable doing this , this is what is working for me. Hope it helps someone.
This is what I have learned about thermostats
- Thread starter the gman
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