Join Date: Nov 2009
Location: Lander, Wyoming
The stock oem 160F thermostat already has a 1mm x 3mm oval air bleed in the outer flange of the thermostat body. No need to make it larger or add additional, imo.
And the factory 'usually' gets them installed with the 'air-bleed' up.
The Thermo-Bob 2 mounts in the same location as your Pro-Cycle radiator by-pass & comes with the 195F thermostat & a spare.
The large body Remote Mounted original Thermo-Bobs are no longer marketed as intended for KLR's.
The T-B 2 does Not work with the IMS 10 gallon fuel tanks, so Watt-man sells a Remote Mounted lower hose Thermo-Bob 3 for that application.
I'm surprised to read that you Modified the Pro-Cycle by-pass to use such a tiny 2mm orifice. You just said that 'flow' is a good thing. A larger flow of 'continuously warming coolant' has proven to be a better thing, at least up to the thermostat set point. Either way, it will stabilize the temp.
There still needs to be a tiny air vent in the top flange of the thermostats to let the air up to the radiator during filling of the system.
The Canadian market KLR650-C series had a coolant flow carb anti-icing system that could easily be converted to a radiator by-pass. The Australian KLR's are still being equipped with carb anti-icing for some unexplained / silly reason. Take note of the 'blank spot' between the hoses on the newer vs older (black paint) coolant pump covers.
Modify at "YOUR OWN RISK"!
Still riding my 1987 KL650-A1. 85,000+ miles & counting