Milky oil please help

[BabyNinjaBrad]

Hello everyone

I recently purchased a 2007 250 with about 7K miles on the clock. I purchased it as a non runner for a winter project. I should have checked the site glass but when I drained the oil it was a milkshake. There was also an excessive amount of oil/coolant mix, probably 3-4 quarts.

The bike however was not low on coolant, so I suppose someone filled it however it was very dark green and looked extremely old.

I ran a compression check on the bike. Cylinder 1 was at only around 120psi and cylinder 2 was around 150, the engine cold obliviously since it doesn't run. At this point I thought it was possible we had a blown head gasket causing the low compression and coolant/oil mix.

I ordered a genuine kawasaki head gasket and took the head off. While I had the head off, I discovered that I had very leaky exhaust valves on cyl 1. I tried cleaning them and lapping them by hand but they were still very leaky. As opposed to getting a valve job I decided to try and find a good used head.

So I got a new head with much better valves. Was supposed to be off a running bike. I also checked the head and cylinder jug for flatness with my precision straight edge and both are very flat in all directions(can't get my smallest feeler gauge under them). I also looked into the coolant passages on the new and old head to see if I could find any cracks and could not visually see any.

The cylinder bores were pretty glazed over, though I could still barely see some cross hatching.

I put the head back on and torqued to spec following the proper order. I also adjusted all of the rocker arms clearances to be right in the middle of the spec range.

I put the carbs back on and put in fresh oil and coolant to the proper levels. I tried turning the bike over a few times and it wouldn't start. I tried to put a little starter fluid in the airbox and at one point it backfired and started a small fire in the airbox

But then I looked in the site glass and sure enough, more milkshake.

So now I am at a loss as where its coming from. Could it be it's just milky from circulating the oil around the passages and clearing it out from before? Or are we still potentially still mixing somehwere?

I had read that sometimes the water pump on these bikes can fail causing coolant to enter the case. I took the water pump out after I drained everything.

I'm not sure exactly what to check for to indicate failure?

The shaft that makes it turn still seems to be tight in the bearing with hardly any play, it spins pretty smoothly. I also put some water in the impeller housing and held it flat for a while to see if any would seep through the bearings, it didn't.

So I'm really at a loss, hoping someone with more experience with these engines has some ideas?

Also as for the compression issue on cyl 1, is this common? The bike sit for quite a while I think, maybe the rings are just stuck?

[Hogges]

If the 250 water pump is anything like the 300 then there is an intentional air gap and drain between the water seal (called mechanical seal) and the oil seal. If either leaks you should see oil or coolant dripping onto the ground. For water to get into the crankcase that way both seals would need to be compromised and in a way that it overwhelmes the drain hole capacity.

[BabyNinjaBrad]

Hi Hogges,

Thanks for the response. I have not seen any coolant or oil leaks from that area.

I looked at the Ninja 300 water pump and the design looks very similar, however they do have different part numbers. From looking at pictures of the 300 I see what looks like a drain hole on the body of the pump. But I didn't see that on my pump when I had it removed.