Details

The Watt-Man Thermo-Bob 2 is a cooling system modification for the KLR 650. In stock form, the KLR runs too cool when ridden in temps below about 80F. The colder outside, the worse a stock bike is. The Thermo-Bob 2 eliminates the inconsistent engine temperature and keeps it running at an optimal 195 degrees. Ultimately this leads to better performance and a longer lasting engine.
• The Thermo-Bob 2 eliminates the inconsistent engine temperature prevalent on the KLR650.
• Allows the engine to maintain a consistent 195 degree operating temperature for better performance and longer engine life.
• Easy installation and made in the USA.
• Kit includes: external thermostat, thermostat housing, bypass hose & fitting, and clamps.

This kit fits all KLR650s: All 32 model years of production. It WILL fit on bike with stock as well as aftermarket 6.6 gallon fuel tanks, but will NOT fit under the aftermarket 10 gallon tanks. For those applications, see Wattman's website for the "Thermo-Bob 3" kit. You can find it here for 1987-2007 bikes, and you can find it here for 2008 and newer bikes.

Kawasaki cut corners in the KLR cooling system, and the Thermo-Bob modifies your cooling system to operate like automotive systems have for decades. In stock form, the KLR runs too cool when ridden in temps below about 80 - 85F. The cooler outside it is, the worse a stock bike is. Plus, the factory cooling system relies on surges of cold coolant every 30 seconds at the bottom of the cylinder to control engine temperature.

The Thermo-Bob is a machined, hard-anodized aluminum external thermostat with a coolant bypass. It allows coolant to bypass the radiator during warm-up, speeding warm-up and eliminating the surges of cold coolant year-round. It also raises the operating temperature at the top of the cylinder to 195°F from 160°F… more importantly, it raises the operating temperature at the bottom of the cylinder to 185°F from downright cold, (ie as cold as 30°F). It should eliminate the out-of-round cylinders that are common to the KLR as it ages which usually results in increased oil consumption. The warmer temps should extend engine life as well as increase oil change intervals, and improve economy by a few MPG. It was the first product to ever receive a 10-out-of-10 rating at Patman Racing, and was strongly recommended by the late Cary Aspy, who was the developer of the 685 and 705 KLR big-bore kits. Cary also liked how this gave more consistent carburetor jetting.

A full technical write-up can be found here.