Removing clutch cover to inspect water pump?

Mb33ch

Joined
Oct 27, 2025
Messages
11
Age
32
Location
East Sussex
Bike
St1100m
Hi all, I recently purchased a ST1100M which im really enjoying riding. I have been inspecting the cooling system as the expansion tank was full of gunk. I'd like to check the waterpump channels are clear and the bearing still turns freely. I've already removed the radiator and timing belt covers. To get to the pump do I also need to remove the clutch and get a new clutch gasket? Or can I simply remove the belt and then pull out the section with the pump on? Thanks
 
Mb33ch said:
Hi all, I recently purchased a ST1100M which im really enjoying riding. I have been inspecting the cooling system as the expansion tank was full of gunk. I'd like to check the waterpump channels are clear and the bearing still turns freely. I've already removed the radiator and timing belt covers. To get to the pump do I also need to remove the clutch and get a new clutch gasket? Or can I simply remove the belt and then pull out the section with the pump on? Thanks
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You can 'spin' the pump without removing it if you have removed the timing belt. Just be sure to refer to 'replacing the timing belt' procedure to have everything lined up for reinstallation. If you wish to remove the water pump you find it very difficult to get out if it has been in there quite a while. The last one I placed I had to knock out from behind which meant removing the carbs. If just clearing the passages, I would leave it in place and remove the hoses on in input/output and try a pressure flush.
 
Cheers, I'll give it a go tomorrow. I have the carbs out already so I'm hoping that will enable to get it out without too much difficulty.
 
Mb33ch said:
Cheers, I'll give it a go tomorrow. I have the carbs out already so I'm hoping that will enable to get it out without too much difficulty.
Click to expand...
The carbs do not have to be removed unless the water pump refuses to come loose.
Then with a block of wood and a hammer you can tap it out from the back.
IIRC, there are not a lot of passages in the pump itself - just the inlet, the 'vanes', and the outlet.
So a good pressure flush should clean it out without removal.
 
wizel said:
www.cmsnl.com

19200MAJG20: PUMP COMP,WATER Honda - buy the 19200-MAJ-G20 at CMSNL

✓ Get the PUMP COMP,WATER ✓ Manufacturer Part Number: 19200-MAJ-G20 ✓ Quality part
www.cmsnl.com www.cmsnl.com
Holm from germany
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Yeah... € 408.00,- + tax + shipment (FedEx)...

an overhauled one from the US:
azv65.com

Honda 19200-MAJ-G20 ST1100 96-03 (1 big nipple) Free shipping USA

Genuine Honda ST1100 96-03 Overhauled Water Pump, Like New Condition, P/N 19200-MAJ-G20 FYI this pump has 1 hose connection that is 13 mm outside diameter and connects to the Crankcase ventilation hose. Both necessary O-rings for installation are included. This pump has been disassembled...
azv65.com

or used ones at eBay...
 
wizel said:
If I absolutely need a specific spare part to keep my motorcycle running and I don't want any other, then price is irrelevant to me.

holm from Germany
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I figure it will still be cheaper than a new motorcycle! ;)
 
I managed to get the water pump out without too much struggle. It was pretty full of corrosion but the bearing seemed really good, no back and forth play and span smoothly. The blades also looked like new (I had the impeller blades disappear on a honda NTV600 before). I've cleaned it up as best as I could and put it back.

Here's a picture from before cleaning.
20260111_161746.jpg
 
I’m interested…how many miles on the bike such that the water pump was that corroded inside? It’s surprising the bearing is as good as you say despite the picture.
 
wizel said:
If I absolutely need a specific spare part to keep my motorcycle running and I don't want any other, then price is irrelevant to me.
Click to expand...
No disagreement from my side...
Only that (particular) spares have grown sparse, resulting in significant price increase... :o-o:
I obtained my last new ST1100 w/pump directly in Japan... long wait, but even with shipment costs and import VAT still significantly lower price then CMS...
I also have repair kits in storage... and got me a shop press for the procedures...
And I'm with @Uncle Phil in this... still way cheaper then any new motorcycle (which won't have nearly the durability to begin with...)

(BTW: fork bottoms where completely unobtainable in Europe... also found in Japan, likely that I got the last new set avail on this planet though...)
 
It's a UK bike, registered 1992, has 118,000 miles currently, I brought it in August with 115,000. From the MOT history it seems almost all the previous mileage was done prior to 2004 and then it did an average of 100 or so miles a year until now. So it's both high mileage and had extended periods sitting unused.
 
Does anyone have any suggestions for a cooling system cleaner? I've cleaned basically all the accessible parts of the cooling system (radiator had been replaced previously and was clean) so it's just the water jacket of the engine, which doesn't seem to be blocked. The corrosion is very solid so I don't want to half free it up and then it start blocking things later.
 
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