Any takers for this riddle?

[dirtbag]

My buddy's 340 Invader was running great last season. This fall he goes to start it and there's no oil in the oil pump case.

We're scratching our heads. Could the seal on the drive have gone bad and the oil sucked into the crank?

One could hardly think a seal goes bad so fast. Again there were no issues last winter.

Any input appreciated.

Wish I had a picture of this sled. It's painted Kawi green with flat black and is the sexiest sled known to man.

[Interceptor398]

When was the last time that oil was changed or topped off?  Some how it got past the seal if it was there?

[Boomologist]

Leaky Banjo?
Did it have oil in bottom end? Did it smoke a lot when started? Was there oil in it to start with?

[mswyka]

Are we talking about injection oil or the oil in the gear case that drives the oil pump?

[gixxer6]

I'm reading it as the oil in the gear case...  In that case, there are 3 possibilities that come to mind: 

1.  Someone forgot to put oil in it the last time it was apart
2.  Bad gear case seal, or oil pump seal and it leaked out into the belly pan over time
3.  Bad crank seal and it was sucked into the crankcase. 

If the seals haven't been replaced recently, I'd bet a melted Invader piston that it's #3...

[mswyka]

I'm reading it as the oil in the gear case...  In that case, there are 3 possibilities that come to mind: 

1.  Someone forgot to put oil in it the last time it was apart
2.  Bad gear case seal, or oil pump seal and it leaked out into the belly pan over time
3.  Bad crank seal and it was sucked into the crankcase. 

If the seals haven't been replaced recently, I'd bet a melted Invader piston that it's #3...

I am with you that a seal failure is the likely culprit.

[dirtbag]

Yes we're talking about the oil pump gear case oil. There was oil at the start, he's pretty good at keeping oil in it.

I agree a bad seal between crankcase and the pump would cause it to get sucked into the case. Just surprised that the seal would go so quick.

[dirtbag]

The leaky banjo? What is that?

[gixxer6]

The banjos are the one way check valves in the oil injection system. 

[Boomologist]

If you are describing the oil level in the sight glass on the side of the engine then yes, the inner seal on the crankshaft is probably bad allowing the oil to be sucked into engine. This is an indication crank seals need replacing.
If you are describing oil missing from the oil tank the most likely is the result of leaky banjo's. They are the brass things that the oil supply lines go to at the intake of each cylinder and the center seal of the block.
Get a copy of a genuine Kawasaki shop manual. It has sections that cover all of these issues.
Good luck.

[dirtbag]

It's gotta be crank seals. We should probably do both his and mine while we're at it.

Where's the best source for seals and what do they run?

Thanks all