New KLR Thermo-Bob Install and Wiring Issues

I recently installed a "Thermo-Bob" on a 2012 bike and snapped a few photos of it's wonderfully clean engine. If you are unfamiliar with this very important mod, here is a brief summary.

Thermo-Bob is a thermostat installed in the KLR's upper radiator hose. It connects to a second fitting installed in the lower radiator hose. When the engine is cold, Thermo-Bob routes engine coolant around the radiator allowing the engine to quickly reach operating temperature. When the engine warms up, Thermo-Bob routes coolant to the radiator to prevent overheating.

This cycle repeats to maintain a near constant 185 degree operating temperature at the lower end of the cylinder. Proper operating temperature reduces engine wear and allows for smoother shifting. For more details on Thermo-Bob, visit  They are great people to work with and I highly recommend them.

Also, with your KLR stripped naked for the Thermo-Bob installation, be sure to inspect the wiring harness. This is a good time to "armor" the wire harness and prevent blown fuses from stranding you in the middle of a thunderstorm (that was an earlier post). This 2012 has a clearly chaffed wire bundle near the horn on the right hand side of the bike. I am confident there are other chaffed spots waiting to be found. This bike's wire harness will be fully armored-up before it goes back on the road.

Thermo-Bob installed in the upper radiator hose.
Looking down at Thermo-Bob

Fitting in lower radiator hose

Lower fitting with bypass hose on upper left

Chaffing wire bundle near horn.