I found a GT750 yesterday on Craigslist

[The Dark Knight]

Some good and I think very bad news.

1. I got the wiring all working, I even took the ignition apart cleaned the contacts and replaced the wires that got cut.


2. It runs and fires on all cylinders and will even idle well. I was even able to kick start it cold.

Now for the bad:

I am loosing all my gear box oil out of the vent on the water pump, I haven't tried putting some in when the motor is running, but almost immediately the oil starts dripping out of the hole on the water pump.

Is that the crank case vent meaning I have bad crank seals? I researched it a lot and I couldn't get a definite answer.

Thanks for the help

[Suzukidave]

If the oil was coming out the vent next to the oil injection pump it could either be a over filled tranny or bad crank seal . With it dripping out the bottom it most likely is a seal on the water pump shaft or the upper O ring that seals the outside of the pump to the case .

[The Dark Knight]

Anybody have tips for replacing this seal? From what I'm reading this pump doesn't look fun.

Will I have to pull the whole assembly to replace it?

[Suzukidave]

Yeah .. the pump will need pulling to work on it and rebuild kits can be purchased through GTReiner . As far as saying if its a easy or hard job to do varies from bike to bike . We have read posts where the pumps came out easy just like they describe in the repair books and then others that put up a fight right from the start . SmokyAllan has even come with a plan that works well for the really stuck pumps viewtopic.php?f=9&t=1956" onclick="window.open(this.href);return false; .

[The Dark Knight]

Thanks for the help Dave.

I am going to try and pull the pump tonight or this weekend, I will let you guys know how it goes.

[The Dark Knight]

I drained the coolant and took the cover off, It looks very clean inside.

If oil is coming right out of the vent hole as soon as it gets there, is that controlled by the seals in the water pump? Or do those seals only keep oil from coming out by running down the pump shaft?

I'm sorry if that is a novice question, I don't fully understand how the vent works. I just want to make sure I am working on the correct part.

[The Dark Knight]

BTW, I only put a quart of oil in and most of it came out.

[Suzukidave]

Lets hope it is the upper seal that has failed as if its part #14 has split or one of its attachment bolts loose it will require you to open the engine . The pump is designed that if oil gets by the upper seal or coolent get by the lower seal there is a hole through the side of the pump body to the vent tube .

[Suzsmokeyallan]

Not to be the bearer of bad news but heres hoping its not the the water pumps line on the breather pipe thats failed. On a Buffalo I bought thats in restoration now, the fitting had corroded by one of the line junctions and any oil going into the transmission automatically came out the weep hole.
The breather line looks like a very short CCI line with two banjo union fittings on it and sits next to the waterpump, one ends on the upper pump casting and the other is on the base of the transmission above the weep hole.
As Dave just stated, If this is the case the engine has to come apart to replace that small breather line.
I'm saying this as a quart is a small amount to have it come back out as the only quantity you put in the engine.
You still need to pull the pump to check its condition and you can test the lines integrity once the pump is out. Applying some low pressure air to the weep hole should result with you hearing it exit the top of the pump casting where the other hole to the vent line is located.

Heres a vent line I grabbed a pic off of ebay, and one of the ends is also broken.

[The Dark Knight]

I agree, I was researching the breather line last night.

So antifreeze only comes out that breather tube when the seals are bad in the water pump?

[The Dark Knight]

Does anybody know the size of the banjo bolts holding the breather line?

[Suzukidave]

They look to be the same as the oil injection banjo's . Why did your vent line check out bad ?

[The Dark Knight]

They look to be the same as the oil injection banjo's . Why did your vent line check out bad ?

Well, this might not be a popular idea, but I am going to use the threads that are there to plug the vent, because the water pump seals seem to be ok. From what I understand that vent only is used when the seals fail, correct?

The reason being, I would like to run the motorcycle some to see if I have to split the case anyway or to make sure there aren't any other problems.

[Suzukidave]

Being its oil and not coolant i cannot see the harm in plugging the system to test the bike out .

[The Dark Knight]

Being its oil and not coolant i cannot see the harm in plugging the system to test the bike out .

I thought about it for a while and it makes sense to me too.

I will drain the oil early to make sure there is not coolant in it, but I already ran the motor with coolant, changed the coolant, then took out the oil drain plug and no coolant was in the gear box.

I just need to figure out the thread, because I don't have any spare bolts that will fit.