Degree wheel

[possum]

To elaborate on what brandon said.

 

Put the wheel on, and rotate the crank and eyeball TDC and set the wheel to 0°. Rotate the crank down a bit and install the piston stop. Now turn the crank till the piston comes up and touches the Before TDC °. Write down the number you see on the wheel, for example we will say 10° is on the wheel. Now turn the crank the other way until you touch the piston stop again, this will be your After TDC°. Write down the number you see on the wheel, for example we will say 14°.

 

So now you need to move the wheel or the pointer, you will want to split the difference of 10 and 14 which will be 12. So with the piston against the piston stop, either roll the wheel 2 degrees or mover the pointer 2 degrees so it at 12°. So you should now be at 12° After TDC. Now turn the crank back down and up, back to Before TDC. And it should also be at 12° now, if not slightly adjust the pointer so it is. To verify keep rolling the motor back and forth until your wheel gives you the same amount of degrees Before and After TDC once the piston hits the stop. That is true TDC.

 

Now you can remove or leave the piston stop on. You can leave it on and double check it, that its still ok if you bump the pointer while working.

 

Now turn the crank down to the top of any port. Lets say the exhaust is 85° below TDC. 85°x2 = 170° its closed. So you have a remaining 190° of exhaust timing. 190+170= 360.

 

Now to check the timing without finding TDC. Put the top of a piston at the top of a port. (I like to shine a flashlight in to see the port just close at the piston). Now set the wheel to 0°, and turn the crank down and back up to where the piston just closes off the port. That is your duration. So essentially you are simulating the stroke of the piston from top of port down and back up to top of port. I personally like this way the best. But thats just me.

 

I hope this all made sense.

[possum]

And to get deck height for squish. I use digital calipers. I turn the piston a lil below the deck, then pull out the bottom of caliper and hang it in the bore against the sleeve. Resting the caliper itself on the edge of sleeve.

 

Now turn the crank up so the piston pushes the caliper in and goes to TDC and back down. So you know you got full height of the piston. Lets say its .010 below deck. So you need a dome with a .032 step to be at a .042 squish.

 

All of this done with whatever basegasket you plan on running in it.

[sheerider11]

Yeah, I read it that way on 250r forums.

Now with the squish, I'll use your numbers.

.010 below deck height

Your looking for .042 squish so a .032 step in the dome.

Now if I run a .016 base won't that make the piston .026 below deck and won't you a.028 dome?

But how much does the base gasket compress when you torque the cylinders?

[RadarRacing]

You have to have the cylinder torqued down with the base gasket in place to do what he is saying. Otherwise of course you cant to deck, step measurements.

[sheerider11]

 

You have to have the cylinder torqued down with the base gasket in place to do what he is saying. Otherwise of course you cant to deck, step measurements.

Oh yeah. Duh

[SOUTHTHIRTY]

Jump on YouTube...there a few good videos on it ....but they are doing it on cars ....but u will get it ...def use the piston stop ..

[BANSHEE HP]

Jump on YouTube...there a few good videos on it ....but they are doing it on cars ....but u will get it ...def use the piston stop ..

 

^yes, thats where i learnt how to port cylinders.

[trickedcarbine]

How bout dis one SB07?

[Toybreaker]

Try harder....

[sheerider11]

How bout dis one SB07?

Ah the good old days

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