I find every ST1100 I look at old or late model low or high mileage has a cracked block so with a laser temp machine I have taken some temps of the RH rear block by the drain screw which appears to be where the cracks start.
Temps of 140c and above have been registered on every bike I have tried all the other cylinders have temps of 100c or even less.
So it seems that the coolant is boiling in the rear and causing hot spots resulting in the cracking.
Looking into the right angle water connections under the carbs it looked like the rear cylinder had a smaller outlet than the rest but by enlarging the clearance in the head did not decrease the temp.
It appears there is virtually no coolant circulation in the RH rear block.
A Band aid fix is to use Waterless coolant such as Evans which they claim has a boiling point of 190c, as this is above the 140c plus measured it may stop the hot spots and help reduce or cure the cracking problem.
Anybody else got any ideas or has somebody got an old cracked block that can be cut open and have a look to see if it can be modified to increase or make the coolant flow in the problem area.
Cheers
Ron
Temps of 140c and above have been registered on every bike I have tried all the other cylinders have temps of 100c or even less.
So it seems that the coolant is boiling in the rear and causing hot spots resulting in the cracking.
Looking into the right angle water connections under the carbs it looked like the rear cylinder had a smaller outlet than the rest but by enlarging the clearance in the head did not decrease the temp.
It appears there is virtually no coolant circulation in the RH rear block.
A Band aid fix is to use Waterless coolant such as Evans which they claim has a boiling point of 190c, as this is above the 140c plus measured it may stop the hot spots and help reduce or cure the cracking problem.
Anybody else got any ideas or has somebody got an old cracked block that can be cut open and have a look to see if it can be modified to increase or make the coolant flow in the problem area.
Cheers
Ron