Home porting question

[bored&stroked]

So I'm using some yamanube porting templates. In the pic we are looking in the exhaust port and see the sleeve overhang [62T 701 cylinder from a raider] I know the red circled part is the port height and can't be touched unless I want a higher powerband. My question is, what about the rest of the sleeve overhang, can that be blended, shouldn't be touched, or doesn't matter really?

 

[Storbeck]

I'm not sure what you mean. Line the top of the template up to the top of the current port, Mark the outline of the template, cut to the line.

Works very well, super easy and dirty cheap.

 

[WFO Speedracer]

A 62T cylinder EX port height comes in around 39.48 from the top of the cylinder , a 760 comes in around 37.42mm so basically 2mm higher , even the 760 still has a slight lip at the top and for sure you don't want it any higher than a 760 cylinder.

Any part of the exhaust port that protrudes below the top of the piston at BDC does nothing because the piston blocks it , check where your piston is at BDC and don't go below that.
I have never used those templates so you will have to excuse my ignorance there but both the 62t AND 64u have flat exhaust port roofs on the 62t you can raise the roof in the middle and create an arched port roof that will give you mor power but it will come on a lot more smoothly than the 760 porting does.

 

[DylanS]

Blend it, bring the curves into the rest of your porting and leave the flat top alone