KDX220 Help

[99tjrockcrawler]

my buddy has a kdx220 that is pumping air into the radiator and blowing it overboard.  He has changed head gasket and water pump seal.  What else can cause this to happen?

[mikesmith]

Well if your sure its pumping air(can you see air bubbles when you run the bike with the radiator cap off before it gets hot?) and the head gasket is good and the heads not warped,why not preassure test the coolant system.Im pretty sure Auto Zone or someplace like that rents/lends a coolant system preassure tester.You should be able to hear the leak if you cant see it,and if it was a water pump seal Im sure your trans fluid would get some coolant in there and turn it white.Does the coolant level go down after the bike sits unridden for a week or so?You could also (or a shop)do a leak down test on your top end.

[DanH1]

Make sure the cap is good and the lip on the radiator where the cap seals is not bent, even alittle. Otherwise the pressure check as mikesmith said is the way to go.    Dan

[teamgreen500]

I can't believe that it could be anything other than the head.

Manny

[Twist-a-grip]

I would tend to agree.  Head gasket.  Was the head torqued to the proper amount? Check for corrosion of the gasket surfaces.
John

[99tjrockcrawler]

Yes he can see bubbles in the radiator and no it does not leak and no it is not mixing into tranny fluid.  I thought it might be a warped head.  How can you tell if a head is warped? Will a new gasket and rtv seal it if its just a little warped?

[teamgreen500]

Answer 1: Take the head off and check it on a surface plate or with a machinist's straight edge -or- the afore-mentioned "Leak-Down" test.

Answer 2: Don't even go there. If the heads warped have it machined straight.

Manny

[mikesmith]

You could try to lap it on a piece of glass if your low on cash.