How to replace head gasket on a 2006 Kawasaki zr 6 j ?

Unless you have a few special tools and EXCELLANT mechanical ability, this should be left to a professional. It may look easy, and it is to a professional, but there are more things to consider. You may have to remove the engine from the frame?.. completely cleaning and prepping both the cylinder and head surfaces for re-assembly. then....re-time both cams to the correct crankshaft location ... checking the valves for sealing, new exhaust gaskets, cam cover gaskets, check intake boots for cracking/leaks... then setting ALL the valve clearances to spec... You get the idea... getting it redone is ALWAYS more expensive than having it done right the first time, MAKE SURE the shop warranties (IN WRITING) their work!

(I guarantee my 2-cycle race motors for 1 race! PERIOD!) In 35+ years only had 1 break.. it broke the crankshaft end off in the main bearing ... (factory defect) BUT, I PAID FOR ALL PARTS and repaired it free!! $$$ouch!!!

sound like the cyl. head gasket has gone . but its worth checking the inlet manifold gasket as there is a coolant port on end of the gasket and coolant can be drawn in to the that way if its the head gasket.there is a head gasket kit you can buy that cures this completley but it means removing the sump and changing the oil rail to prevent the clamping load changing with eng. temp
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with car running check to see if the radiator hoses get rock hard and stay that way.. when a cylinder head gasket goes the commpression from the cylinder will push into the cooling system causing the hoses to become hard at all times even after t-stat opens... if u have a funnel that can lock onto radiator where the cap would normally be then you can actually watch the coolant bubble and smell exhaust coming from the coolant...

1. Oil plug gasket 2. clutch cover gasket, 3. Center case leaking
4. TOO much oil in crankcase, 5. Shift shaft seal. 6 Counter shaft seal.

Check you main jets ccccccthey could need a good wiring through with needle wire cleaners or try running it without any air cleaner unit .If it runs well then could be an air filter problem.

make sure when you check the oil that the bike has been sitting on the centre stand for about twenty minutes or so before you check it as there is still alot of oil in the cylinder head and oil coolers etc,sitting the bike will let the oil drain back to the sump and give you a correct reading,try this and see how you go,hope this helps

sounds like bad gas.