Author Topic: Piston - To window or not to window?  (Read 2930 times)

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Offline Wopper

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Piston - To window or not to window?
« on: November 17, 2015, 05:57:45 PM »
Hi all;
I have posted here a couple of times, have an 03 K5 I am doing a top end rebuild on,  ( yes, I have checked the crank play, and seals, all good )

My question now is whether or not to have my new piston window cut??? I have read most of the threads on top end rebuilds, and various other topics.

I have done the porting clean up, and wasn't planning on doing any other mods.

I am using the bike for Ice Racing, ( run 4-5 gear mostly ) and the bike only gets 3-4 hrs a year running.

Need to have some advice from guys that have had both stock and window cut pistons, and what is the difference?? :?

Cheers, Wopper
 
« Last Edit: November 19, 2015, 04:07:28 AM by Wopper »

Offline alexander-vmann

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Re: Piston - To window or not to window?
« Reply #1 on: November 18, 2015, 09:50:49 AM »
your k5 has 6 gears?  :?
KX 500 newbie

my bike: 1993 kx500

Offline Wopper

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Re: Piston - To window or not to window?
« Reply #2 on: November 19, 2015, 04:09:35 AM »
Ok;
Got it, running a Wiseco forged piston, -----and need to correct LOL, 4-5 gear, I also found the piston window thread here, read it through so I am going for the window!!  8-)
Thanks!

Offline Wopper

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Re: Piston - To window or not to window?
« Reply #3 on: November 26, 2015, 03:32:16 PM »
So, got the top end completely apart, doing some measurements on the squish…….As I calculate it:

1.  0.6 mm for head step
2.  0.13mm  for piston to deck Gasket supplied with Wiseco Kit is only 0.25 mm, (Stock is 0.5 ) Wiseco Piston has slight dome, measured at TDC and outside dia.
3.  1.0 mm Thick OE head gasket



Total Squish = 1.73 mm  Is this correct, am I supposed to calculate piston to deck clearance??  :| :?

Optimum Squish, as I do want a rev engine 1.5-1.6mm??  :-D
« Last Edit: December 01, 2015, 10:18:31 AM by Wopper »