CR4C Thermo-Bob Kit


This kit is for the 2017-2020 CRF450R and CRF450RX, which have no factory thermostatic control.

Add Spare Thermostat * 

The Thermostat is the only consumable in the system, some people get one now for the future.


Without any factory thermostatic control, coolant temperatures vary widely.  These engines have EFI – and when used on a snowbike, the system then overfuels, thinking the bike is constantly in ‘warm-up’ mode.  The Thermo-Bob 3 is a machined aluminum housing with a 180°F (82°C) thermostat inside, and modifies your cooling system to operate like automotive systems have for decades… keeping coolant flowing all the time through the engine, but not through the radiators until it is up to a selected temperature.

There is also a threaded port in the Thermo-Bob 3 that will accept aftermarket temperature gauges such as the KOSO or TRAIL TECH 1/8-28 BSPP temperature sending units.

A full technical write-up when used on a Kawasaki KLR650 can be found here.