Drilling out exhaust on the side attached to engine

[JStok]

Does anyone know what size drill bit to use to drill out the head of the exhaust pipe? Are there any suggestions of how to do it? How much faster will it go if I do this?

[Wheelman-111]

Greetings:

JStok axed:

Does anyone know what size drill bit to use to drill out the head of the exhaust pipe?

It doesn't matter. It's a Bad Idea.

Are there any suggestions of how to do it?

Yes. Don't.

How much faster will it go if I do this?

It's far more likely to slow down, until it stops because the engine overheats.

[Mystic]

he may be talking about the restriction in the header where it bolts to the cylinder

[Wheelman-111]

Greetings:

Upon reflection, Mystic is probably right. My mistake.
A grinding stone and not a drill is the answer. Mounted on a Dremel, Roto-Zip or proper die-cutter, the restricting washer is ground away until flush with the walls of the headpipe.

Be SURE to verify the carb jetting once you're done. If you open up the pipe, the stock (68?) jet can no longer supply sufficient fuel to keep up with significantly increased mixture demand. In conjunction with this and proper variator tuning and sufficient oil supply (Add 100:1 premix to your pump) a stock "P" restricted model moves smartly up from a top speed of 30 to something north of 40.

[JJ Joseph]

the stock (68?) jet can no longer supply sufficient fuel to keep up with significantly increased mixture demand

The stock unrestricted jet is #75, and that should be OK without adding oil to the mix. No harm in adding oil, but if it's running too oily, you can cut back on the mix. Too much oil never hurt a 2-stroke, but it gets messy.