Hi
I just finished installing a Cylinder works big bore kit on my KFX 400 yesterday. I bought the bike with a shattered case due to a thrown chain. I replace the bottom end with one from another bike and then bolted on the top end kit. After breaking in the piston and setting the rings, I checked the oil. It was white and frothy and my coolant shows signs of oil sheen. I installed new Cometic gaskets when putting this together and torqued to factory specs. WHat could cause a new gasket to fail? These were all new parts with new gaskets. Anything else I should look for before completely tearing it down? The bike ran and idles great. Thanks in advance for any insight.

 

I just pulled the water pump housing. I figured here was as good of place to start as any. From what I read, for 2005 and 2006 they made the housing out of magnesuim and it was prone to corroding and seal failure. I pulled mine and yes indeed the housing was corroded and there was bleed by of coolant into the clutch housing cover. I had the cover from my 2003 bottom end so I replaced it for the 2006 cover. The '03 cover is near perfect as was made from aluminum I guess so it did not have this problem. I buttoned it all up and will have to wait until tomorrow for oil, new filter, and coolant. My fingers are crossed that this will solve the problem.

 

That may to it...Are your pump seal and propeller got damaged from some debris....