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Honda ST1300 motorcycles thermostat failure

October 31, 2008

I hope no one minds my intrusion but while in the process of doing research trying to find the cause of a very high percentage of thermostat failures I ran across this website.
Owners of Honda ST1300 motorcycles experience a 90+% thermostat failure.It is an aluminum engine and radiator.The thermostat housing is not bolted to the engine block,but is free standing connected only by rubber hoses. The factory installs a wire to a connector attached to a T-stat housing bolt that runs to a ground lug on the chassis.
Thermostat failures occur at very low mileage and are repetitive.
Upon removal and inspection of the T-stat there is some type of build up present that causes the moving parts to bind.The buildup is brown in color and can be removed with an abrasive.
A theory has developed that there may be some kind of electro-chemical,for lack of a better term,process occurring.
The owners manual calls for a mix of AF/distilled water while the service manual recommends AF/distilled and deionized water.It is unknown what is originally installed from the factory or dealer.
Any knowledge shared would be appreciated.
Thanks,

Steve Roddy
- Atlanta, GA, USA

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Sounds like good old fashioned rust to me. Can't a dealer find out what the factory installs in the cooling system? Is Honda dealing in super secret motorcycle technology?

Sheldon Taylor
supply chain electronics
Wake Forest, North Carolina
November 5, 2008