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Thread: Cag port timing
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post #10 of (permalink) Old 03-20-2019
Join Date: Mar 2008
Posts: 21,721
Re: Cag port timing

Originally Posted by edek91 View Post
If I set my ports at

Ex duration 175

Tranfer duration 125

Ex from tdc 92.5

Tranfer from tdc 117.5

So I'll have to machine the ports higher in the cylinder.

I already use my snap on gloves to stop me getting blisters ha. I was just worried too much squish will cause me to lose revs.
Yep the good old hand rub......As far as machining the ports...Yes you will need to...Keep the same roof angle at the top and youll be good..

To do the exhaust port its easier to cut it in angled or better known as "Canted"..The Canted exhaust port will flow aces and not thin down the aluminum dangerously at the exhaust flange inner snout........

As far as the squish...Good old mildly modded performance engines start out at .060"-.065" of squish on a stock head without a basegasket...

2pc/3pc cylinders start delivering descent power at .045" of squish..I prefer a nice even .040" for a descent overall and easy to tune playtoy...

I finetune the squish of the 1pc cylinders using a piece of granite tile with a 2 1/8" hole cut in it and use 100 grit sandpaper glued to the granite with center cut out aswell to put the cylinder on and spin back n forth til I get the desired squish then I adjust the ports and even grind-in an extra boost port

Another thing I wanted to touch base on is the difference in pistons.....On my builds where I want the tightest squish without having to grind the base or mill the top lip you can simply take a piston ported 43cc/49cc piston and use that aslong as your crank has a 10mm pin..

As you can see the piston ported piston top is like almost 1 1/2 millimeters higher than the reed inducted piston..Both pistons in the picture below are linked together on a single 10mm pin for accuracy...

Last edited by CAM2; 03-20-2019 at 01:15 PM.
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