KT4A Thermo-Bob Kit

These are popular choices as snow bikes but since there is no factory thermostatic control, the coolant temps vary widely.  The EFI sees cold coolant and overfuels, thinking the bike is constantly in ‘warm-up’ mode.  The Thermo-Bob 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 4 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.