Once again porting thread

Carlos motors

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I feel kinda stupid for posting porting thread but I have troubles with a lot of english words and while I try to understand everything there is a lot of there that I still dont get it. So here are few questions.
1) is porting on 66cc actually worht it? How much hp would you get with proper setup ( exhaust,carb)?
In .2 .3 hp range or betweeen .5 and 1hp?
2) if I understood there is porting and port timing. Porting means just taking metal off and port timing how that works while engine is running. Question is can you give me numbers let say you need to take of 1mm of each side on exhaust port and intake port? Or how much in height should ports be? Do I trimm just down side or upper side to?
3) Should I round all edges from outside of ports to inside of port and edge where port meets the cylinder?
4) Would this set be good for porting?

Sorry for this much question but there is so much information out there and everybody has some theory.
 

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For a beginner a safe bet is to just widen the ports and not mess with the heights until you have a better understanding of port timing and have a degree wheel.

Significant gains can be had from port matching the transfers to the case, and widening both intake and exhaust without changing the height and timing of any ports.
 
I agree, just match your intake and exhaust ports, concentrating on the width and not so much the height. Don't mess with the transfer ports or try to sleeve it or anything, unless you do it correctly you could mess it up.
 
Ok
So how much should I widen the ports? Intake and exhaust same amount?
Also should i try to widen intake manifold or make a new one (same with exhaust)? Would it make a difference?
 
Ok
So how much should I widen the ports? Intake and exhaust same amount?
Also should i try to widen intake manifold or make a new one (same with exhaust)? Would it make a difference?
They should match up with your intake and exhaust connections. Also, if there are any burrs in the intake that could restrict fuel you should smooth it out.
 
Also should I deal with transfer ports or is it better to leave that out for now?
It's easy to make a mistake on the transfer ports, if you've seen one done and know how much to take off and where you can do it. If you don't know, I wouldn't do it until I knew. If you mess it up, it's going to cost about $20 for another stock one.
 
The best and safest way to do the transfers unfortunately requires you to split the case to make sure you don't contaminate the crank bearings. You want to use the base gasket to match both the bottom of the cylinder and the case inlet, which is almost always off a LOT from the factory. Don't go far into the case unless you have an aftermarket jug that needs it and you know what you are doing - it will increase case volume and lower compression if you go too far and these engines love compression. Usually they are off at least ~1/4" on one side in one direction, and the same amount on the opposite direction on the other side. Some just take the jug off and stuff the case with an oily rag to catch the shavings, then clean the bottom end with gas or hot water afterwards but I'd rather split the case and do it right.

Makes a big difference. Along with deburring the ports, slightly widening them, zero decking the jug, and taking the end cap off the muffler you can get a stock kit to 40+ mph on flat land with no parts purchased at all. You can see in this pic after grinding but before polishing that the top part of the transfer matched up perfectly out of the box, but the bottom was off by ~ 1/4" or more. On the other side, the corresponding top was off and the bottom was fine.
93732
 
So my dremmel tool arrived and I will start learning now and I found few old cylinders so I want to know which of this 2 exhaust port is better and why? Is it just because of size or is it because of shape?
 

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