Coolant gushing out of my tailpipe after water pump rebuild

Gotanubike · Post by **Gotanubike** » 06:03 pm Jun 13 2013

So I recently acquired this bike, running and seemingly in pretty good shape. The first thing i was told to do was check my water pump. I did, and found the impellar bolt had been broken and water pump had not been working. When I drained the coolant, only maybe 1/2 a litre came out. So I fixed it up with an impellar bolt, some new oil seals, etc....

Just now I try to start it after filling with coolant, following instructions to bleed the air, etc etc...It didn't start, so I pulled the plug and it was wet and grey coloured. Great..I figured what the hell, so I dried it off and cleaned the plug it the tried starting again. I started this time, only very boggy and spiting a LOT of coolant out....

Now I've been told this is maybe not caused by damaged internals but by water in the crank case that just needs to be pushed out...If anyone has has any experience with anything like this or atleast shed some light on perhaps where I can start to address this problem...I just really wanna hope t doesn't need to be rebuilt...

royadams · Post by **royadams** » 06:27 pm Jun 13 2013

My guess would be a head gasket. If you have water in the crank case you definitely don't want to run it. You will ruin your cylinder. When water pump leaks it goes into transmission not the crankcases.

Post by **KDXGarage** » 06:28 pm Jun 13 2013

Turn it upside down with the spark plug out.

Post by **dfeckel** » 06:33 pm Jun 13 2013

The bike was probably overheated pretty severely when the impeller bolt broke, which likely blew the head gasket. Now it's leaking coolant into the cylinder via a poor sealing head gasket. I would pull the head and take a good look at the cylinder for damage. At minimum, you need a new head gasket. If the cylinder looks damaged, you might be in for a replate and new piston, rings, and small end bearing. If the cylinder looks good, this might still be a good time to throw a new piston in there any way.

Gotanubike · Post by **Gotanubike** » 06:39 pm Jun 13 2013

royadams wrote:My guess would be a head gasket. If you have water in the crank case you definitely don't want to run it. You will ruin your cylinder. When water pump leaks it goes into transmission not the crankcases.

There is no hole or crack in the world known to be able to introduce this much water into a combustion chamber...I mean it was like seriously explosive diarrhea.

Wouldn't I have noticed compression and running issues with the bike?

royadams · Post by **royadams** » 06:42 pm Jun 13 2013

There's only one way water of any kind can get in there and that's through the cylinder or head

royadams · Post by **royadams** » 06:45 pm Jun 13 2013

I should say one way unless its under water then the carb and pipe.

Gotanubike · Post by **Gotanubike** » 07:01 pm Jun 13 2013

Ok when I get a chance I will post some pics of what I find ;)

Gotanubike · Post by **Gotanubike** » 07:55 pm Jun 13 2013

And the award for the fastest engine tear-down goes to.....

J/k it was easy

Here's what I found...all races around the gasket look sealed... but unquestionably, this thing is pulling in copious amounts of water somehow

Post by **bufftester** » 09:30 pm Jun 13 2013

Looks like you were using it to mix cement for the front porch! lol

Broken impeller I'd check for warpage on the head/cylinder mating surface, visual on the gasket isn't much use. Other possibilities include a crack somewhere in the water jacket. Might be a good idea to pull the jug and take a look at the bottom end as well as suggested earlier. Cylinder doesn't look too bad, but a good cleaning is in order first.

Gotanubike · Post by **Gotanubike** » 09:38 pm Jun 13 2013

Is this the stock piston?

Gotanubike · Post by **Gotanubike** » 10:09 pm Jun 13 2013

I checked for warping on the cylinder head by holding it against a mirror and it isn't warped.

Also, if the head gasket was indeed the culprit, would there not be at least some heat scoring on the outer races?

Gotanubike · Post by **Gotanubike** » 11:12 pm Jun 13 2013

Pulled engine mid section(jug)...seems fine, other than I wouldn't know if something was wrong but no visible signs of cracking. Reeds are mint...Not sure about the KIPS or exhaust advancer deal but seems to work fine I think...

Gotanubike · Post by **Gotanubike** » 11:56 pm Jun 13 2013

One last thing, to give you guys an idea, I could have just filled a milk cartoon 3/4 full of antifreeze with what i dumped out of my spark arrestor. The bike ran maybe 15 seconds...

Post by **KDXGarage** » 02:07 am Jun 14 2013

Button it back up and pressure test the cooling system.

Gotanubike · Post by **Gotanubike** » 09:44 am Jun 14 2013

Guess it's all I can do...new head gasket on monday...I'll try again but I think it might be pulling water in from one of the ports..

royadams · Post by **royadams** » 11:33 am Jun 14 2013

The bike hasn't been parked out side has it. It seems odd that the bike could even turn over, none the less run if it pumped that much fluid through the crank case.

Post by **KDXGarage** » 12:10 pm Jun 14 2013

KDX's are tough.

That is NOT a stock piston. Wiseco has laser scribing like that on top. I am not sure about other brands.

Gotanubike · Post by **Gotanubike** » 04:59 pm Jun 14 2013

royadams wrote:The bike hasn't been parked out side has it. It seems odd that the bike could even turn over, none the less run if it pumped that much fluid through the crank case.

I don't know, I just got it a few weeks ago. I keep it inside...and yea, it surprised the heck out of me. At first I thought, "yes it finally started!" and my mom, who was standing in front of me and yelled at pointed at the back of the bike. At first I thought it was just the overflow...a second look and a bit of a rev and coolant is shooting 4 feet out the tail pipe.

Jason wrote:That is NOT a stock piston. Wiseco has laser scribing like that on top. I am not sure about other brands.

No way! I'll have to have a closer look at it tonight to identify it...

royadams · Post by **royadams** » 06:01 pm Jun 14 2013

Its possible the exhaust was filled with water through the silencer opening. I don't think the bike holds anything close to a gallon of coolant.

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