Cutting the Spree head to raise compression, how to.

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Dac
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Cutting the Spree head to raise compression, how to.

Post by Dac »

Thank you keithw for this great information and great pictures.

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Hello all,

Just cut a Spree head to raise the compression for better performance. Here are some pictures.

http://datsunroadsterranch.com/scooter/headcut1.jpg

http://datsunroadsterranch.com/scooter/headcut2.jpg

Here is a stock head. Note the small step at the edge of the combustion chamber. This step is about .020". This is the reccomended maximum cut.

http://datsunroadsterranch.com/scooter/headcut3.jpg

Chucked it up in the lathe, centered and squared it. This can also be done on a mill.

http://datsunroadsterranch.com/scooter/headcut4.jpg

Time to cut.

http://datsunroadsterranch.com/scooter/headcut5.jpg

.020" removed.

http://datsunroadsterranch.com/scooter/headcut6.jpg

Layed some 320 grit wet and dry on the drill press table. This is used to remove the tool marks and make sure that is completly flat.

http://datsunroadsterranch.com/scooter/headcut7.jpg

http://datsunroadsterranch.com/scooter/headcut8.jpg

Note the little step is now gone. If you want to cut more off you need to watch for piston interferance.

http://datsunroadsterranch.com/scooter/headcut9.jpg

Stamped the amount cut off to prevent future confusion.

keithw
"Its not what you ride, its that you ride"
1996--------Honda Elite S-
1991--------Tomos Targa-
And a Bunch of other bikes.
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