Heaviest bike ever owned, my new 2004 ST1300A is an amazing machine, destined to bring much happiness! For safety & reliability, and to learn the machine, now into a discovery / investigation mode since acquiring last December. Full electrical inspection, connector cleaning, loom condition, with replacement of two sub-looms due to heat damage and cracked insulation on wires. Repaired the battery box. Replacing the ECT sensor and working on newer coolant hoses (looking for a coolant flow diagram and/or pictures). Dang, there are two tons of wire, connector plugs, fuses, looms, and tape! Lots,of fun!
First posting; Hello!
- Thread starter SafeRider
- Start date
Welcome to the forum! 
Hey there! Congrats on your “new to you” 1300 and welcome to the site from Eastern Ontario 
Welcome to the club!
ToddC
Site Supporter
Welcome from WA STate!!
T
Just ask and your questions will answered.... Best forum ever..!!
T
Just ask and your questions will answered.... Best forum ever..!!
- Joined
- Sep 5, 2018
- Messages
- 1,778
- Age
- 70
- Location
- Newlyn, Penzance, Cornwall, UK
- Bike
- 2000 ST1100Y
- STOC #
- 9006
Welcome from Cornwall UK! All you need on here to keep your new ST running sweetly.
Welcome aboard!
Welcome, BlueST is the faSTest, it has been scientifically proven!
- Joined
- May 27, 2021
- Messages
- 1,059
- Age
- 63
- Location
- Coquitlam British Columbia Canada
- Bike
- 2009 ST1300
Welcome from Coquitlam and congrats on the ST, and yup, it's heavy, but it's got all the greatest stuff, handles the dirty wind with ease...
There's no end to what you'll find here and a tremendous amount of help available, there's nothing like it.
I've reinterpreted / rewritten how I understand the cooling system which I've cut and will paste below. I've taken it from my understanding of the 2003 manual.
Coolant Flow
Coolant enters the pump from two sources; the right side radiator hose and the coolant bypass hose.
Primary coolant flow is pumped into the block past a branch channel and diverges through two channels near the center of the block then turn outward and flow between each cylinder pair. Flow diverges again to flow around the outside of each cylinder, then converges and exits each cylinder bank primarily through the o-ringed right angle connector past a branch port, through a hose to the back of the thermostat housing.
Close to the outlet of the pump, the branch channel upstream of the divergence flows to a port on the right side of the block. A hose connects from the port and runs across the top of the block down the back of the left side of the engine, through the oil cooler, through another hose back to the back of the thermostat housing.
From the thermostat housing, coolant flows from the backside through the bypass hose to the inlet of the pump, and when the thermostat is open, through the thermostat outlet and hose to the left side of the radiator. Flow continues from left to right across the radiator to the hose connecting to the water pump.
Note: The bypass is a fixed and uncontrolled parallel flow path to the thermostat valve - hose – radiator – hose path. With the thermostat wide open, some flow must still occur in the bypass.
Left and Right cylinder bank right angle branch connectors.
Coolant from the left connector flows through a hose which routes around the outside of the right TBs to the inlet of the SE Thermal Valve. The outlet of the valve is connected to a hose which connects to a three port converging tee.
Coolant from the right connector flows through a hose which is connected to the second inlet port of the converging tee.
The outlet of the tee connects to a hose which flows out to the right side of the radiator below the cap.
Note: What is the purpose of the right side branch circuit upstream of the tee. Is this the plastic tee which fails.
There's no end to what you'll find here and a tremendous amount of help available, there's nothing like it.
I've reinterpreted / rewritten how I understand the cooling system which I've cut and will paste below. I've taken it from my understanding of the 2003 manual.
Coolant Flow
Coolant enters the pump from two sources; the right side radiator hose and the coolant bypass hose.
Primary coolant flow is pumped into the block past a branch channel and diverges through two channels near the center of the block then turn outward and flow between each cylinder pair. Flow diverges again to flow around the outside of each cylinder, then converges and exits each cylinder bank primarily through the o-ringed right angle connector past a branch port, through a hose to the back of the thermostat housing.
Close to the outlet of the pump, the branch channel upstream of the divergence flows to a port on the right side of the block. A hose connects from the port and runs across the top of the block down the back of the left side of the engine, through the oil cooler, through another hose back to the back of the thermostat housing.
From the thermostat housing, coolant flows from the backside through the bypass hose to the inlet of the pump, and when the thermostat is open, through the thermostat outlet and hose to the left side of the radiator. Flow continues from left to right across the radiator to the hose connecting to the water pump.
Note: The bypass is a fixed and uncontrolled parallel flow path to the thermostat valve - hose – radiator – hose path. With the thermostat wide open, some flow must still occur in the bypass.
Left and Right cylinder bank right angle branch connectors.
Coolant from the left connector flows through a hose which routes around the outside of the right TBs to the inlet of the SE Thermal Valve. The outlet of the valve is connected to a hose which connects to a three port converging tee.
Coolant from the right connector flows through a hose which is connected to the second inlet port of the converging tee.
The outlet of the tee connects to a hose which flows out to the right side of the radiator below the cap.
Note: What is the purpose of the right side branch circuit upstream of the tee. Is this the plastic tee which fails.