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Kxf 250 piston 2014 2015 compatibility swap fitment

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Has anyone tried a pre 2014 piston in a 2015 onwards model Kxf 250? The part numbers are different but the diameter of the piston is the same and the valves are the same. Has anyone tried it? Is it a higher comp piston in 15 onwards that's what the change is?

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In a crunch or a fire sale opportunity, I have used pistons from different years. *****> I have not on this specific year though.

I buy/get the new piston I suspect is the same. Then I take the old one out. Using callipers and mic, measure the two for same/different; using wrist pin hole as reference point. Then I decide if it will work. If close enough, it goes in. If not, the new piston gets returned for something else.

 

 

 

 

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Thanks I have measured the clearance between the plug and the top of the piston and have 0.5mm without the top gasket installed.  Only thing I can't measure is piston to valve clearance and valve angle. The valves are the same diameter. Any suggestions? Apart from run it and see?

 

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Here's one or two.

1. Put the head and cylinder together (no gasket), upside down on the work bench. With no rings on the piston, slide the piston in and seat it all way down until it stops. At this point it is in contact with the head. Try to rock and also rotate the piston at that place. If it sits flat and turns 360 with no catches, pass. If it rocks/knocks or catches, fail

2. Install the piston and cylinder on the engine. HAND turn the crank to TDC. Is the piston outer rim proud of the top of the cylinder? Even or less, pass. Proud, fail. Hand turn to BDC, does the skirt contact the crank?

3. Install the head, (no head gasket), install cams, time them, spark plug etc. By HAND slowly turn the crank. Nearing TDC feel for any contact resistance. Do 4 full rotations to be confident of all valve positions. No contact pass. Contact fail.

Pass all above? Then take it apart, install gaskets, torque it down, fill with fluids, go for a start

You may need to test fuel octane level to get it to run sweet. Start low and go up, noting if any difference.

 

Hope that helps!

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