After gave a range and stabilized the system. I am a believer.
Glad you like your Thermo-Bob, Trundlebike! My riding partner, whose technical opinion I respect, likes his also, with 55,000 miles on his '08.
As mentioned, the Thermo-Bob stabilizes coolant temperature more fully, and at a higher operating temperature, than the stock cooling system.
What are the maintenance, performance, and service life consequences of the Thermo-Bob's greater coolant temperature stabilization and higher operating temperature? Improvements may indeed exist; however, don't know of quantifiable, repeatable data supporting such improvements (e.g., data indicating increased reliability/durability/performance). Don't know of any component failure from "thermal shock," or "heat-cycling" with the stock cooling system, but they may exist also.
Temperature gauge needle excursions/fluctuations don't bother me, as long as the needle stays out of the far-right red zone. Air-cooled engines experience deeper heat-cycles and temperature fluctuations without compromising reliability; I've assumed the KLR650 engine is designed and manufactured with materials, clearances, operating parameters, etc., taking into account the stock cooling system's characteristics and capabilities, or vice-versa. My only evidence supporting the premise is, high-mileage, long service life KLR650s without benefit of the Thermo-Bob.
If I'm in error, I'll surely pay dearly for my doubts and skepticism!
Again, nothing against the Thermo-Bob and its users; an innovative product, marketed with integrity. I consider the Thermo-Bob an OPTION, not a NECESSITY, as do some with evangelistic imperative.
Not that I consider the as-built KLR650 design and materials perfect and sacrosanct; I have an Eagle Mike doohickey and torsion spring, an Eagle Mike mirror/clutch lever relocation bracket, Eagle Mike upgraded subframe bolts on my Generation 1; not to mention some Allen-head machine screws replacing JIS "Phillips-head" fasteners here and there, the TPI
5-1/4"-wide rectangular mirrors w/dampers, the Tusk handguards w/spoilers, the TPI headlight bulb and relay harness, the TPI windscreen, the Cycleracks rear rack, and the Race-Tech high-output stator and heavy-duty rectifier/regulator I've installed. Plus, EBC 320-mm front brake rotor, steel-braided front brake line, and Galfer Green pads. I confess, I've even performed the "Tee mod" and the 22-cent mod!
The KLR650 ain't perfect, as it comes from the factory, and IMHO, the machine can be improved. The Thermo-Bob may certainly be an improvement.