Water pump ST1100 vs ST1300

[increasing]

I see that oil can come out of the drain hole on the water pump on the ST1300 when the seal against the oil-lubricated bearing becomes poor.

Surely that can't happen on the ST1100... or?

 

[Larry Fine]

Surely that can't happen on the ST1100... or?

 

[increasing]

The water pump on the ST1100 is driven by the timing belt, but can oil get in there?

 

[ST1100Y]

The water pump on the ST1100 is driven by the timing belt, but can oil get in there?

Not quite...
Unless a seal of the cam drives fails...

 

[increasing]

As I read these pictures, there is no possibility of oil leakage in or in connection with the water pump on the ST1100 that can occur on the ST1300. I'm not thinking of oil leaks elsewhere that could get into the cooling water.

 

[Larry Fine]

I'm sure the belt vs chain is what makes the difference.

 

[billo]

I'm sure the belt vs chain is what makes the difference.

Unless the belt oil seal goes of course.

 

[increasing]

That's true, but compared to the ST1300 on the ST1100 no oil comes out of the drain hole on the water pump.

 

[ST1100Y]

I'm not thinking of oil leaks elsewhere that could get into the cooling water.

on pre '95 models a leaking oil cooler might cause such... in theory... never heard of one failing though...
or of course a defective head gasket on any 1100 model year... also rare though...

ST1100 w/pump has one weep-hole to protect the t/belt & drive, designed that "leaks" behind the pump case (shown in your first photo)

ST1300 w/pump features two weep-holes, one on the drive/oil side of the shaft, the other on the coolant side; both also venting outside to prevent contamination of lubricant and/or coolant media...