Biturbo Retrofit For Pacer Moped

I've recently decided that it's time to revive my Pacer moped, which has been sadly non-functional since September.

To remedy my previous exhaust problems, I bought a new Biturbo exhaust for it. All I need to figure out now is how to attach the old exhaust pipe (22mm outside diameter) to the new Biturbo muffler (27mm internal diameter, I think). Obviously this needs to be some sort of airtight solid fitting. I've heard of brazing and welding them together...I just need to figure out how to shim the difference in diameters out before I can attach them together.

Any suggestions, besides getting a custom pipe made?

Re: Biturbo Retrofit For Pacer Moped

It depends on how crude you want to be

Crude.... Just use a large flatwasher or lockwasher to make up the difference.

Also crude... you could make a ring out of 1/8th inch dia rod...(this is what I would do..weld or braze it up))

Less crude... Make a short cone section out of sheet metal... (not easy to do correctly)

The overall length of the pipe is what determines what RPM you make your peak HP at.. the longer the pipe the lower the RPM your peak HP occurs at.

Re: Biturbo Retrofit For Pacer Moped

Okay, I think I'm gonna go with welding the 1/8" rod to make the shim.

My next question: (please excuse my ignorance)

When you talk about "HP" in reference to RPMs and exhaust pipe length, what does "HP" mean?

Re: Biturbo Retrofit For Pacer Moped

HP = HorsePower

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