Thermo-Bob 3: Kit Contents, Example results before and after
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This kit fits all Ninja 250s: From 1988 to 2012.  Please see other kits for Thermo-Bobs which fit other motorcycles.

Kawasaki cut corners in the Ninja cooling system, and the Thermo-Bob modifies your cooling system to operate like automotive systems have for decades.  In stock form, the Ninja 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). 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 of a Thermo-Bob on a KLR650 can be found here.

  • Item #: TB3-N

Thermo-Bob 3 for Kawasaki Ninja 250: ALL MODEL YEARS

Price: $129.00
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