F2 mod?

[CuriousJojo100]

Can a f2 thrust exhaust be modified to work better with these motors? I am running the “100cc” steel cylinder 2 piece jug. It’s been port matched, ngk “6” plug, upgraded carburetor(looks like NT style but cleaner, no primer button, red filter cover. I played with the stinger size by using epoxy and opening it up little by little between runs. Ran with the most power with the opening as big as it could be. Is the tip being cut at an angle having a negative effect? Powerband kicks at the very top of my rpm range

 

[ImpulseRocket]

My 2 cents. By the time you modify that F2 to be a good match to that engine if yours, it won't be an F2 anymore. In my opinion they aren't much better than a stock exhaust with an extra hole drilled in the end. An MZ65 or WC80 (close to the same as the MZ) are probably the best off the shelf bolt on pipes you can get if higher RPM power is what you are after, and even they aren't really ideal, just much better than most. With modification people also use Jog pipes with great success.

 

[GW's Motorized]

I've heard good stuff about the cdh66. It's basically a pre modded jog pipe

 

[robe]

Looks like there are two styles. The first example is what I think is the CDH66

Amazon.ca

CDHPOWER CDH66 Exhaust Expansion Chamber Muffler-48cc/80cc Gas Motorized Bicycle | eBay

CDH66 muffler fitting on 2 stroke gas motor engine kit gas motorized bicycle;. - CDH66 muffler fit on well on most cylinder heads including CNC head;. CDHPOWER Support Team. We will do our best to resolve the issue.

www.ebay.com

 

[GW's Motorized]

Looks like there are two styles. The first example is what I think is the CDH66

Amazon.ca

CDHPOWER CDH66 Exhaust Expansion Chamber Muffler-48cc/80cc Gas Motorized Bicycle | eBay

CDH66 muffler fitting on 2 stroke gas motor engine kit gas motorized bicycle;. - CDH66 muffler fit on well on most cylinder heads including CNC head;. CDHPOWER Support Team. We will do our best to resolve the issue.

www.ebay.com

Oops, I meant cdh 67.

 

[Andrew1234]

My 2 cents. By the time you modify that F2 to be a good match to that engine if yours, it won't be an F2 anymore. In my opinion they aren't much better than a stock exhaust with an extra hole drilled in the end. An MZ65 or WC80 (close to the same as the MZ) are probably the best off the shelf bolt on pipes you can get if higher RPM power is what you are after, and even they aren't really ideal, just much better than most. With modification people also use Jog pipes with great success.

What pipe is optimal?

 

[ImpulseRocket]

What pipe is optimal?

Off the shelf? Not a single one. Much like communism, some things work, most don't, and some are more equal than others.

 

[Chainlube]

This is probably the best out of the box pipe, it has a better divergent cone than any of the MZ type pipes. It has a wide open stinger, so that will be loud and make power in the higher rpm range. The stinger looks like it has an OD of 22mm, which would accept a new 19mm OD pipe inside. Cut the most of the existing stinger off, put a new stinger inside and clamp it down. Make the new stinger long enough that you can push 5 or 6" inside, this will change the rpm range where the pipe makes it power.

Amazon.ca

 

[CuriousJojo100]

This is what I need than. Is there any cutting I can make to lower the powerband on the f2 to lower the little powerband it does give?

 

[GW's Motorized]

This is what I need than. Is there any cutting I can make to lower the powerband on the f2 to lower the little powerband it does give?

From what I've heard the F2 is basically a straight pipe. Maybe cutting the stinger off and putting a smaller diameter stinger would help.