GT750 Water Pump - shaft is different

[Whit]

I just ordered a water pump and now that I started taking off the old one I see the shaft is different than on the one that I bought. I looked up part number on Bike Bandit for 72-75 and they all have the same part number. I have a 1973 model and the shaft is keyed to fit the cutout on the water impeller. The one that I bought just has a round shaft and the shaft has a pin through it.
Did Suzuki have two different types of pumps for the GT750 or did I just get some other model pump? Thanks //Pat

[Whit]

Just ready the GT750 field guide and found out the early models had a keyed shaft. Crap I should have looked at the Field Guide first. Oh well now I need to sell a pump and find one that fits. //Pat

[tz375]

You just need a later model impeller. Some have slots for both the key and the pin. I may even have a spare here we can swap out but I'd have to check what's out there.

You could also cut/machine a slot to take the roll pin.

[Whit]

That would be great if you have one to swap me. Now that I know it is just the impeller I will get back to trying and pull the old one with the slide-hammer method. //Pat

[Ridge Runner]

Pat
Yes they did have two style pumps. 1972 and early 73s were the same. Then sometime late 73 they changed to the pin style. I have a 1972 and just changed my pump. I ended up the same problem you are having. What I did was I took a file on edge and machined the slot in mine down. You have to cut it down even with the top of the empeller, otherwise it wont push on the shaft far enough to get the snap ring on the bottom. Worked fine for me.
Larry

[tz375]

According to my notes at least I have a couple of early style impellers, but as Larry mentioned, you can file the slot down until it's more or less level with the blades. Check it to make sure it fits all the way down far enough to get the small circlip on.

If you still want to swap one out, PM me your address etc.

[Whit]

Thanks TZ for the offer but I was able to use Larry's suggestion and file it down. What was amazing was that my pump came out rather easily. I grabbed the shaft with a pair of vice grips and then put another set of vice grips on the first ones and tapped it with a hammer. After about 25 taps it came out. I am pretty sure this will fix my oil leak from the weep hole and hoping it will stop the coolant from finding its way into my oil. Thanks everyone for your help. //Pat

[Coyote]

hoping it will stop the coolant from finding its way into my oil.

.
Not a 100% certain, but I believe that is caused by a bad seal between the transmission and the water channel. That seal can only be replaced by splitting the cases. Anyone?

[tz375]

Water in the oil could be two bad seals in the pump or could be from the O ring that sits between the two case halves.

[Whit]

I am hoping my old pump had two bad seals as I sure don't want to split the engine. I guess I will find out in about 3 weeks as that is how often I have been changing my oil over the past one year. One nice thing about the new pump is I don't have to stick cardboard under the engine to catch the oil.

[Coyote]

could be from the O ring that sits between the two case halves.

yeah TZ. That's the one I was thinking of.

[Whit]

Just an update. Replacing the water pump fixed the oil leak from the weep hole but I am still getting water in the oil. I guess splitting the case is in my future. //Pat

[Suzsmokeyallan]

Two things could be happening there, the bypass joint has failed or the weep hole short tube has a leak. The bypass joint on 72 and some 73s has been known to fail as theres no 0-ring used on those models. The weep hole tube has been known to fail as the pot metal unions can break off, both of these issues will put coolant in the oil. If the weep hole is not leaking oil or coolant then your bypass joint is failing internally.