If the Bosch is only $60, it wouldn't be too excessive for someone that has a spare HD pump to pickup a Bosch pump and compare the two. It wouldn't be too hard to test flow rate on the HD pump either.

Personally, I'm not losing any sleep over if and when my pump goes south.

 

Just maybe...someone will ask Bosch. If they fit and work the same, my bet is they will be happy to tell you

 

Interesting. I'm watching to see if anyone tries this.

 

I wouldn't mind at all to try it if I needed it. Someone make them for HD, could it be Bosch, maybe.

 

The more I think about it, I don't think the flow matters...

The pump is a magnetically coupled design.... nothing directly drives the impeller. The impeller is mounted on a magnetic drum, and spins on a shaft. Surrounding that drum is another drum with magnets in it. As the outer drum spins, the inner spins along with it. I think this might actually be part of the system design. There is a point of restriction in the cooling system... on the 14-16 models it's probably the thermostat. As I understand it 17+ has no thermostat & the ECU controls turning the pump on & off.... in that case the restriction point is probably the coolant tubes going into the heads. I think the pump, when it's on, is designed to have the motor run full tilt & constantly "slip" on the magnetically driven impeller. The impeller spins as it can holding a constant pressure against the restriction point.... the restriction point controls the flow. On the 14-16 models when the thermostat is closed the impeller doesn't spin at all but the motor is still full RPM.

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When the thermostat is closed the coolant is circulating through the engine and thermostat housing. Coolant is always moving somewhere when the pump is running.

 

Makes sense, I forgot the thermostat had 2 outlets.

I still would bet the impeller "slips" most if not all the time depending on restrictions to control the flow.

__________________________________________________ ____
For ROCKOUT information & purchasing please click HERE For all Twin Cams and Evo Big Twins & Sportsters

 

bosh makes the abs modules for the rushmore bikes. it wouldn't be too much of a stretch if they supply mo co with coolant pumps.

 

I have a strange feeling HD is gonna scrap the hole water cooled thing anyway's.

 

damn good post. I prefer air cooled bikes which to me was a benefit of a Harley. No tears if they scrap the head coolant system. I never had a water cooled anything that did not eventually leak but water pumps should be dependable.
From other posts, I think coolant leaks damage the pc boards to cause water pump failures, but I really do not know if this is true in all cases.