Engine Porting - Gases out, Fuel Air in

[Egor]

Anyone out there doing any porting? This is a biggie, although you have to manage the throttle with some discretion this was the biggest boost for my China engine. If I were to put an expansion chamber with the carb and ports I don't think the rest of the parts would hold up. I will not even bring up 4th and 5th ports. I wanna hear what you are doing. Have fun, Dave

[JosephGarcia]

I really beleive you have taken these engines farther than any of us ever have. I've only heard of carb modifications, and expansion chambers.

Dave, you got pictures?

[Egor]

I can put up some pic's. Ill also get all the mesurments for you so you can replicate them. I want to hear from one of you after you do it, now that will be fun. I started porting Hodaka's back in the day, you could do the same thing to this engine but it would never hold up to the pressure. I think we were getting 15 HP out of 100cc. 10,000 rpm so you can see what around 80cc could do. Have fun Dave

Originally Posted by Bikeguy Joe

Dave, you got pictures?

Nah, not gonna port mine, I want it to last awhile.

[Egor]

The porting is like this. You can take it to the limit or anywhere in between. I have a mild port and it gets the engine running cooler and idles perfect, when you twist the throttle it has considerable more power, but if you were to abuse it, it would not last long, but if treated proper it should last just as long. If you have no will power then you should not go there. My example to HP is to show what a 80cc engine is capable of. Have fun, Dave

PS: The pic is a mild port, notice the intake is just covered see how much exhaust is showing, Bad air out, Good air in.

So you're saying just grind the exhaust port so it's a little bit higher?
I have a bunch of different files around here somewhere and a Dremel.

Looks too easy. I do have a gentle throttle hand.

[dave1490]

i port matched the exhast to the pipe the best i could{1 retanguler the other is round}removing all the casting flash and opening it up right to the bracket also in the pipe i 45 degreed the holes and slighty enlarged them,it helped a fair amount.am going to build an intake from scratch using play-do to get the right shape then fiberglassing it with resin{got to decide if i want low rpm{long and thin}or max power{short and thick}.and might use a 20-25mm carb.

[SlicerDicer]

I may mess with the Dax motor like this once I convert to the Tecumseh I think it would be neat to mess with it if nothing else.

[ibeenjammin]

What the heck is casting flash?? and how did you remove it?