GT750 Current Water pump options?

[The1970's]

Hi all,

I know this topic has been beat to death over the past few years but I had a couple new ideas and wanted to hear your thoughts. I'm going through a rebuild on my 750 and I have almost no usable parts related to the water pump. My impeller is broken into 3 pieces, the pump shaft is pitted badly where the seal rides, and the pump body is badly corroded. Not to mention all the usual seals are shot. Looking around it seems a new water pump cartridge is going to cost me almost $400 and I can't even find an impeller for sale anywhere.

Has anyone tried running an electric water pump? I know the stock ones work fine and if I had all the parts, that's what I would prefer. But the goal for this bike isn't to be factory correct. A small electric pump would pull only 1 or 2 amps and could be run either continuously with the factory thermostat, or remove it and use a pump controller. If I really wanted to I could also remove the water pump drive and save a few pounds, though I would have to fit a digital tachometer into the factory housing. My main concern with this is 1. how long the pump will live? and 2. how well the factory alternator will hold up to that additional load? I figure it could be done for about half the cost of buying all the factory water pump parts, any thoughts?

[Alan H]

Yup. The originals have worked for nearly 50 years. The lekky ones for considerably less.
Do it once and do it right.
One or two amps. Is that 1 x 13(v) = 13 watts, or 2 x 13v = 26 watts? Double the power, is it needed and what's the flow rate?
More details required to give advice and make decisions, and the original design works right as the pump speed varies as the engine speed does, unlike an electric pump which will be constant(?) speed no matter what the engine needs - whether the engine is cold (thermostat closed) or hot (stat open).
Of course, you may know better than Suzuki........

Oh, refurbed water pumps are available here - ebay number 254827973843 . And they work as Suzuki intended. There's one in mine and it's worked fine for the last 4 years since I had the bike completely refurbed by the pump supplier - and it isn't a trailer queen, it gets used for touring, mainly 2 up + panniers and top box as well as (currently) an occasional thrash.

[The1970's]

Well you've found the cartridge for a good bit cheaper than I could, even with shipping to the states. Thanks for that if I do go that route. In the ad it does look like it is the earlier style shaft with the keyway instead of pin. Does it matter which I use as long as I get the impeller to match?

If I did decide to go the electric route the best options seems to be a pump made by Davies Craig. Specifically their model EBP23. From my research I believe this is the same part supplied in some Cadillac cars with V6 engines (whether this is the engine coolant pump or for some other coolant is unclear). They list the pump at a maximum of 20 L/min and 1.1 Amps. This is the same pump that BDK sells in a kit for the GT750, they say it's tested to 20,000 hours. However, I can't find longevity information from the manufacturer so who knows. The pump can be wired as you described (constant full speed) OR it can be installed with a pump controller that will respond to engine temperature. Essentially the pump could be programmed to be off during warmup and increase its power as the engine temperature increases.

I'm not trying to reinvent the wheel here...I just know that the electronics technology has come a long way since my bike was new in 1975 and it's already getting electronic ignition so figured I would at least explore the idea. The goal is to build a mostly-stock looking bike that does everything a bit better than stock. I don't really plan to tour on it but I do ride my bikes quite a bit locally. Reliability isn't a major concern but I don't want to be replacing my water pump every year either.

[Rassie]

I have a brand new impeller. Bought it tentatively when I replaced a pump fully expecting to break the original one. Heating it up with a cutting torch made it come off in one piece. So no longer need it. I know they are like hen's teeth. Message me if you want to take it off my hands.